WATERMAN, Circuit Judge:

The petitioner, John Indiviglio, appeals from an order entered on January 8, 1979, in the United States District Court for the Eastern District of New York (Mishler, Chief Judge) dismissing his petition brought pursuant to 28 U.S.C. § 2255 to vacate his conviction and to set aside his sentence. The judgment of conviction was entered on August 16, 1974, after trial by jury. Indiviglio was found guilty of participating in a narcotics conspiracy, in violation of 21 U.S.C. § 846, and was sentenced to a term of twelve years imprisonment and to a special parole term of five years. The judgment of conviction was affirmed without opinion by this Court on January 29, 1975. United States v. Matteo, 510 F.2d 968. Certiorari was denied, 421 U.S. 998, 95 S.Ct. 2394, 44 L.Ed.2d 665 (1975).

On May 10, 1977, Indiviglio filed the present 28 U.S.C. § 2255 petition. Indiviglio based his petition to vacate the judgment of conviction on the following four claims: (1) ineffective assistance of counsel; (2) prosecutorial suppression of exculpatory evidence; (3) admission of illegally seized evidence at his trial, in violation of the Fourth Amendment; and (4) his own alleged incompetence to stand trial due to his low intelligence, which compounded the deleterious effects attaching to his claim of ineffective assistance of counsel.

After a lengthy evidentiary hearing, the district court rejected all these claims and dismissed Indiviglio's 28 U.S.C. § 2255 petition. The district court found that the performance of Indiviglio's trial counsel satisfied constitutional standards; that Indiviglio, although classified as between "Dullnormal" and "Borderline" in intelligence, was competent to stand trial and to assist his attorney in his defense; that Indiviglio's Fourth Amendment claims had been waived by his failure to present them prior to trial in accordance with Fed.R.Crim.P. 12(b) and the principles of Davis v. United States, 411 U.S. 233, 93 S.Ct. 1577, 36 L.Ed.2d 216 (1973); and that, in light of Stone v. Powell, 428 U.S. 465, 96 S.Ct. 3037, 49 L.Ed.2d 1067 (1976), Fourth Amendment claims are not cognizable in 28 U.S.C. § 2255 proceedings. We affirm the district court's order.

The proceedings culminating in the conviction of Indiviglio which he now challenges were initiated by an indictment brought against Indiviglio charging him and his co-defendants, Frank Breene and Thomas Matteo, with having conspired with one Frank Aguiar and others to violate the federal narcotics laws. Indiviglio and Breene were tried together; the case against Matteo was severed.

The first prosecution witness called at Indiviglio's trial was Tyler Somas, an admitted co-conspirator with a criminal record who received special consideration in return for his cooperation. Somas testified that he had been employed at Indiviglio's auto parts store beginning in 1965. Somas further testified that during the period of his employment with Indiviglio he had become involved in a narcotics business operated by Indiviglio and Matteo; that Indiviglio had set up laboratory equipment in a downstairs storage area of a building he owned, which equipment was employed by Indiviglio to manufacture synthetic heroin; that Somas believed that he was present in this storage area on one occasion and saw Indiviglio give drugs to Matteo; that Indiviglio met with Matteo and Somas to discuss the financing of a trip Indiviglio was to make to France to meet with a heroin supplier; and that Matteo had instructed Somas to obtain heroin from Indiviglio.

Finally, Somas testified regarding certain conversations he had had with Indiviglio at the latter's Long Island residence in the early part of 1971. Somas related that Indiviglio's drug business and money that Matteo owed Indiviglio were the principal topics of discussion. This portion of Somas's testimony was partially corroborated by his wife, Fay Somas. Mrs. Somas testified that she was present at Indiviglio's Long Island residence on one of these occasions and heard her husband and Indiviglio discussing Matteo, the millions of dollars Indiviglio claimed to have made from his drug business, and his use of foreign cars to smuggle heroin into the country.

The prosecution also called Frank Aguiar, one of the persons named in the indictment, as a witness. Aguiar testified that he had received heroin from both Tyler Somas and James McCormick, with the latter indicating to Aguiar that he in turn had received the heroin from Indiviglio.

In addition, the prosecution introduced at trial numerous items of physical evidence, consisting primarily of pieces of chemical equipment and documents and letters addressed to Indiviglio. All of these items were seized during a search of Indiviglio's Long Island residence, which search was prompted indirectly by a Suffolk County police officer's discovery of Thomas Matteo, armed, severely wounded, and in possession of an attache case containing approximately $350,000, on the premises. We will discuss the circumstances surrounding the search of Indiviglio's residence and the seizure of the physical evidence more fully in connection with our treatment of Indiviglio's Sixth Amendment claims, infra.

Finally, as part of the prosecution's rebuttal evidence against Breene, a pair of Drug Enforcement Administration (DEA) agents testified that they saw Indiviglio and Breene in Beth's Bar Grill on May 24, 1974.

In his petition, Indiviglio claimed that his Sixth Amendment rights were violated by the alleged egregious incompetence of his trial counsel, Ludwig Abruzzo. United States v. Wight, 176 F.2d 376 (2d Cir. 1949), cert. denied, 338 U.S. 950, 70 S.Ct. 478, 94 L.Ed. 586 (1950), first enunciated the standard employed in this Circuit for determining the adequacy of representation by counsel:

[U]nless the purported representation by counsel was such as to make the trial a farce and a mockery of justice, mere allegations of incompetency or inefficiency of counsel will not ordinarily suffice as grounds for the issuance of a writ of habeas corpus . . ..

A lack of effective assistance of counsel must be of such a kind as to shock the conscience of the Court and make the proceedings a farce and mockery of justice.

Id. at 379 (footnote and citations omitted).

This Court has continued to adhere to this standard for three decades. See, e. g., Curci v. United States, 577 F.2d 815, 819 (2d Cir. 1978); United States v. Bubar, 567 F.2d 192, 201-02 (2d Cir.), cert. denied, 434 U.S. 872, 98 S.Ct. 217, 54 L.Ed.2d 151 (1977).

Indiviglio points to several acts and omissions at trial, which he contends demonstrate Abruzzo's incompetence: (1) inadequate cross-examination of witnesses Tyler and Fay Somas and Frank Aguiar; (2) refusal to permit Indiviglio to testify in his own behalf; (3) failure to elicit certain exculpatory and impeaching information; and (4) failure to object to the introduction of items seized pursuant to an unlawful search.

However, Abruzzo did cross-examine Tyler and Fay Somas, pointing out their long criminal records and their involvement in narcotics dealings and suggesting the existence of "deals" made with federal authorities in exchange for cooperating with the prosecution. Frank Aguiar was similarly cross-examined. Abruzzo's cross-examination of the police officer who conducted the search of Indiviglio's Long Island residence revealed the important fact that no trace of narcotics was found on the chemical equipment seized from the premises. Abruzzo called three witnesses who testified to Indiviglio's reputation for honesty and integrity in the community. Moreover, Abruzzo called an alibi witness to testify that she had seen Indiviglio at his home in Bayside at the time when the DEA agents had placed him at Beth's Bar Grill with Breene. The remaining information that Indiviglio claims Abruzzo failed to elicit is for the most part either peripheral to the issues and of only slight impeaching value, or wholly implausible. Finally, Abruzzo's failure to call Indiviglio as a witness is understandable from counsel's viewpoint, because Indiviglio wanted to testify that he had amassed the $350,000 in cash, discovered in Matteo's possession at Indiviglio's Long Island residence, from real estate transactions, and had kept it hidden in a barrel in his basement. As Chief Judge Mishler noted below with reference to this story, "[T]hat would be pretty tough for a jury to believe."

There remains Indiviglio's claim that his counsel's failure to raise certain Fourth Amendment arguments conclusively establishes counsel's incompetence. A brief factual background is necessary in order to assess the merits of this claim.

On September 27, 1972, Lt. John T. Thomsen of the Suffolk County Police Department responded to a call reporting that shots had been fired at an address subsequently determined to be Indiviglio's Long Island residence. Upon Thomsen's arrival he looked in the back window of the house and saw a pair of legs sticking out from behind a refrigerator. Thomsen broke the window, entered the house, and found Thomas Matteo lying face down on the floor with five bullet wounds in his back. Matteo was holding a loaded revolver in his right hand, and an attache case containing approximately $350,000 was on the floor next to him.

Shortly thereafter, another Suffolk County police officer (Gentles) arrived on the scene to investigate the shooting. While on the premises he observed what appeared to be gambling papers, records and receipts. On the basis of these observations, Gentles then obtained a search warrant from the Suffolk County District Court to continue his search of the premises for similar items. In the process of executing this warrant, Gentles discovered items similar to those commonly used in the testing and dilution of narcotic drugs. This information was conveyed to another member of the police force (Thompson), who upon examining the paraphernalia on the premises, determined that a narcotics manufacturing operation might be involved, and accordingly sought to procure a second search warrant from the Suffolk County District Court.

To justify his request for a warrant, Thompson prepared an affidavit setting forth the facts outlined above, and additionally stating that information obtained from the Bureau of Narcotics Dangerous Drugs revealed that Indiviglio had a "prior substantial involvement in illegal narcotics traffic." On the basis of the information contained in this affidavit, a second search warrant was issued. The chemical equipment and documents offered into evidence by the government at Indiviglio's trial were obtained during the execution of this search warrant on September 29, 1972.

Subsequent to Indiviglio's trial and conviction, his wife initiated a civil action in the United States District Court for the Eastern District of New York against the police officers who conducted the searches of Indiviglio's Long Island residence. See Indiviglio v. Blomberg, Docket No. 75-C-1379 (E.D.N.Y. 1978). In that action, Judge Bartels ruled that the initial warrantless police intrusion exceeded permissible limits, and consequently invalidated both search warrants subsequently obtained by the police.

At Indiviglio's trial, Abruzzo challenged the admission of evidence seized during these searches on the grounds that the seizure of the evidence took place before the applicable warrants were issued, which challenge properly was rejected by the district court. Abruzzo at no point attacked the admissibility of the evidence seized during these searches on the grounds that the search warrants themselves were invalid. We note, however, that appellate counsel (who was different from trial counsel) also made no attack on the validity of the search warrants. Nor did Indiviglio's present counsel set forth this argument in his 28 U.S.C. § 2255 petition. This issue was raised for the first time at the district court hearing on Indiviglio's petition only after Judge Bartels had ruled the search warrants invalid in the aforementioned civil proceeding.

In this situation, where the initial police intrusion was made in response to a genuine emergency situation that required prompt attention, and the subsequently-issued search warrants were obtained through proper channels and appeared valid on their face, we are not prepared to conclude that Abruzzo, as well as Indiviglio's two other attorneys, displayed incompetence in failing to spot this intricate issue or in neglecting to anticipate Judge Bartels' ruling. Thus, in this case, Abruzzo's failure to make a presumably meritorious pre-trial suppression motion does not automatically lead to the conclusion that he was either ineffective or incompetent in representing Indiviglio at trial.

Accordingly, in light of the above, and having carefully examined the record as a whole, we cannot conclude that Indiviglio's trial was a farce or a mockery of justice, nor was representation of counsel such as would shock the conscience of the court. Moreover, Chief Judge Mishler, who observed the proceedings both at Indiviglio's trial and at the hearing on this petition, commented that Abruzzo "did a pretty good job" in conducting Indiviglio's defense. We are convinced that the district judge's conclusion as to the adequacy of counsel is not erroneous and we hold that Indiviglio has not established his claim of ineffective assistance of counsel.

As to Indiviglio's claim that his low intelligence and mental incompetence to stand trial exacerbated the ineffective assistance of counsel, we observe that Chief Judge Mishler ordered a psychiatric examination to assess Indiviglio's ability to stand trial, and thereafter conducted a hearing on this issue. After listening to the testimony of two psychiatrists and a number of lay witnesses, the district court concluded that although Indiviglio was below average in intelligence, he nevertheless had the mental capacity to understand the charges against him, to discuss the evidence against him and to prepare for trial. The district court further found that Indiviglio's mental deficiency did not substantially affect the ability of counsel to render effective service. Having reviewed the transcript of the hearing below, we conclude that Chief Judge Mishler's findings of fact on this matter are not clearly erroneous.

Finally, we address Indiviglio's Fourth Amendment claim, previously raised in connection with his ineffective assistance of counsel argument, a claim which he contends should be a sufficient ground by itself alone to justify a collateral attack on his conviction. As mentioned above, however, Indiviglio's present theory as to the invalidity of the search warrants, which tracks the reasoning expressed by Judge Bartels in ruling on the identical issue in the related civil proceeding, never was presented in Indiviglio's original trial court proceedings, but was raised for the first time at the hearing below upon the present petition.

As Chief Judge Mishler correctly noted, Fed.R.Crim.P. 12(b) requires that motions to suppress evidence be made prior to trial. In addition, Fed.R.Crim.P. 12(f) provides that "Failure by a party to raise defenses or objections or to make requests which must be made prior to trial . . . shall constitute waiver thereof, but the court for cause shown may grant relief from the waiver." This Circuit has interpreted Rule 12(b) to mean that a failure to assert before trial a particular ground for a motion to suppress certain evidence operates as a waiver of the right to challenge the admissibility of the evidence on that ground. See United States v. Braunig, 553 F.2d 777, 780-81 (2d Cir.), cert. denied, 431 U.S. 959, 97 S.Ct. 2686, 53 L.Ed.2d 277 (1977); see also United States v. Rollins, 522 F.2d 160 (2d Cir. 1975), cert. denied, 424 U.S. 918, 96 S.Ct. 1122, 47 L.Ed.2d 324 (1976); United States v. Indiviglio, 352 F.2d 276 (2d Cir. 1965), cert. denied, 383 U.S. 907, 86 S.Ct. 887, 15 L.Ed.2d 663 (1966). Moreover, as the Supreme Court held in Davis v. United States, 411 U.S. 233, 93 S.Ct. 1577, 36 L.Ed.2d 216 (1973), the waiver provisions of Rule 12(b) apply regardless of whether an accused seeks to raise his constitutional claims for the first time on direct appeal from his conviction or raises them first on his collateral attack on that conviction in a 28 U.S.C. § 2255 petition. As the Davis Court stated:

We believe that the necessary effect of the congressional adoption of Rule 12(b)(2) [12(f)] is to provide that a claim once waived pursuant to that Rule may not later be resurrected, either in the criminal proceedings or in federal habeas, in the absence of the showing of "cause" which that Rule requires.

411 U.S. at 242, 93 S.Ct. at 1582-83.

Indiviglio asserts that the necessary showing of "cause" required to excuse the failure to present his Fourth Amendment claim at trial is supplied by the alleged incompetence of his counsel in neglecting to raise this claim at trial. We note that it is irrelevant whether counsel's failure to raise at trial Indiviglio's present Fourth Amendment claim is characterized either as a matter of sheer inadvertence or as one of professional judgment that a motion on such grounds would have been unsuccessful, because neither is sufficient to constitute "cause" within the meaning of Rule 12 and Davis, even assuming that Indiviglio's present Fourth Amendment claim is meritorious. See Polizzi v. United States, 550 F.2d 1133, 1138 (9th Cir. 1976) (good faith ignorance of legal grounds for objection does not excuse a failure to comply with Rule 12(b)(2) [12(f)]); Lumpkin v. Ricketts, 551 F.2d 680, 682-83 (5th Cir.), cert. denied, 434 U.S. 957, 98 S.Ct. 485, 54 L.Ed.2d 316 (1977) (petitioner's only allegation of cause — that trial counsel provided ineffective assistance in failing to make an objection — must be rejected; otherwise, requirement of showing cause would effectively be eliminated).

Without some showing that counsel's mistakes were so egregious as to amount to a Sixth Amendment violation, a mere allegation of error by counsel is insufficient to establish "cause" to excuse a procedural default. As we already have concluded, the incidences Indiviglio cites here to support his claim of ineffective assistance of counsel, whether viewed separately or collectively, amount to little more than ineffectiveness by hindsight. We agree with Chief Judge Mishler's characterization of Indiviglio's strategy as a "bootstrap effort to evade the requirement of the rule." Therefore, we hold that inasmuch as petitioner was aware of the existence of the search warrants and the government's intention to introduce the fruits of the search as evidence at his trial, and because Indiviglio had ample opportunity to present his claim in a timely manner and to elicit prior to trial the facts upon which to base his present theory, interests of finality in criminal judgments and the necessity of sanctions to effectuate orderly rules of procedure mandate that he be precluded from raising his Fourth Amendment claim at this late date.

We affirm the order of the district court.