TORRUELLA, Circuit Judge.

In this habeas corpus action, appellant was convicted of first-degree arson in Rhode Island. He claims that the trial judge excluded an alibi witness in violation of his Sixth Amendment rights, and we agree.

In the prosecution's request for discovery information prior to trial, the prosecution specified that the suspect fire started between 11:00 p.m. and 12:00 a.m., on June 7, 1986, at his apartment building in Pawtucket, Rhode Island. In complying with the request appellant did not aver an alibi defense, although Rhode Island Rule of Criminal Procedure 16 requires a defendant to provide such notice within 21 days of receipt of the state's demand. Appellant claims that he was unaware of any alibi for that evening between 11:00 p.m. to 12:00 a.m. Appellant prepared his defense accordingly.

At trial, the state presented the testimony of Donald Byrne, a fire investigator. On cross-examination, he stated that the fire actually started thirty to forty-five minutes before it was discovered. Appellant's counsel then calculated that, according to the inspector, the fire must have started between 10:49 and 11:04 p.m. This new time period obviously was somewhat removed from the 11:00 p.m. to 12:00 a.m. period that counsel had previously focused on in preparing the defense.

The revised time window suggested a new defense. Counsel remembered an affidavit, supplied during discovery by the state, from appellant's common-law wife, Doris Palmieri. Ms. Palmieri stated that appellant had picked her and her sister up at a club in Providence sometime after ten o'clock. Because a witness placed appellant at the building at 10:34 p.m., and others saw him there before then, counsel inferred that he did not leave to pick up his wife until after approximately half past ten.

Counsel then tracked down Ms. Palmieri's sister, Jenette Fagundes, and learned that after picking up the sisters at the club, appellant drove her home before returning to Pawtucket. Counsel determined that appellant could not leave Pawtucket after 10:34 p.m., drive to the club in Providence, take Ms. Fagundes to her home in Providence, and return to Pawtucket in time to start the fire by 11:04 p.m. Appellant therefore could not have burned down the building.

After the state closed its evidence, and five days after the fire inspector testified, counsel petitioned the court to allow Ms. Fagundes to testify. He stated that he did not recognize the relevance of her story until the fire inspector testified about when the fire started. Furthermore, he did not learn Ms. Fagundes' name or address until two days later. The state responded that it would not oppose the motion if it could introduce Ms. Palmieri's statement, which contained incriminating facts, in full as rebuttal. In it, Ms. Palmieri revealed that upon arriving at the apartment building, appellant told her that she should sleep elsewhere.

The trial judge took a recess to ponder the matter and ultimately decided to exclude Ms. Fagundes' testimony. The judge noted that appellant had the Palmieri statement well before the trial, and that it sufficiently raised the possibility of the alibi. Because Rule 16 imposed an affirmative duty on appellant to disclose reliance on an alibi, even if the name of the witness was unknown, the judge found that appellant had violated discovery. The judge excluded the alibi testimony as a sanction under Taylor v. Illinois, 484 U.S. 400, 108 S.Ct. 646, 98 L.Ed.2d 798 (1988). The judge determined that defendant "seized upon this tact having heard the state's entire case and the state rested," and cited the need to ensure the "orderly administration of justice."

In contrast to the proffered alibi, the inculpatory evidence at trial was substantial. Two eyewitnesses saw appellant in the vicinity of the fire overcome by smoke; one saw him running from the building. Another eyewitness saw appellant throwing lighted paper into a vent leading to the first floor of the building. Witnesses testified that appellant threatened the building's owners shortly before the fire. Another witness apparently testified that appellant had warned the witness to leave the building. Swayed by this evidence, the jury rendered a guilty verdict and appellant received a 25 year sentence.

Appellant bases his argument on the Sixth Amendment, which states: "In all criminal prosecutions, the accused shall enjoy the right . . . to have compulsory process for obtaining witnesses in his favor." Of course, the "right to compel a witness' presence in the courtroom" would be meaningless "if it did not embrace the right to have the witness' testimony heard by the trier of fact." Taylor, 484 U.S. at 409, 108 S.Ct. at 653. Exercise of the right thus assists the adversary process in its truth-seeking function by ensuring that the trial court hears the full array of admissible facts pertinent to the case. The Court in Taylor noted that "few rights are more fundamental than that of an accused to present witnesses in his own defense." Id. at 408, 108 S.Ct. at 652.

It is not an absolute right, however. Given the demands of the adversary system, the Court in Taylor found that a trial court may exclude a defense witness without trampling on the Sixth Amendment. The Court issued no hard test; rather, it listed various considerations that a judge could use as a guide. These include the "integrity of the adversary process, which depends both on the presentation of reliable evidence and the rejection of unreliable evidence, the interest in the fair and efficient administration of justice, and the potential prejudice to the truth-determining function of the trial process." Id. at 414-15, 108 S.Ct. at 656. If these concerns outweigh the defendant's interest in presenting witnesses, the trial court can properly exclude the testimony.

Courts thus have upheld the exclusion of a witness when a party willfully violates the discovery rules to gain a tactical advantage in litigation. In Taylor, for instance, it was "plain that the case fit into the category of willful misconduct in which the severest sanction is appropriate." Id. at 417, 108 S.Ct. at 657. The proposed testimony appeared to be fabricated — "witnesses [were] being found that really weren't there." Id. In Michigan v. Lucas, ___ U.S. ___,___, 111 S.Ct. 1743, 1748, 114 L.Ed.2d 205 (1991), the Court explained its earlier holding: "We did not hold in Taylor that preclusion is permissible every time a discovery rule is violated. Rather, we acknowledged that alternative sanctions would be 'adequate and appropriate in most cases' " (quoting Taylor, 484 U.S. at 413, 108 S.Ct. at 655). The Court in Lucas justified the imposition of the severest sanction of exclusion in Taylor by noting the willful character of the discovery violation.

Indeed, most circuit court cases affirming exclusion in response to discovery violations involve willful conduct. See United States v. Johnson, 970 F.2d 907, 911 (D.C. Cir. 1992); United States v. Mitan, 966 F.2d 1165, 1175 (7th Cir. 1992); Horton v. Zant, 941 F.2d 1449, 1467 (11th Cir. 1991); United States v. Peters, 937 F.2d 1422, 1426 (9th Cir. 1991); Eckert v. Tansy, 936 F.2d 444 (9th Cir. 1991); Escalera v. Coombe, 852 F.2d 45, 48 (2d Cir. 1988); Chappee v. Vose, 843 F.2d 25 (1st Cir. 1988). The Ninth Circuit has even interpreted Taylor to mean that exclusion is permissible only when the case involves misconduct. Peters, 937 F.2d at 1426.

In this case, there was no such misconduct. Appellant did not, and could not, learn that the fire was set between 10:49 to 11:04 p.m., until the fire inspector was cross-examined at trial. Appellant proceeded on the theory that 11:00 p.m. to 12:00 a.m. was the relevant time period simply because the government suggested that it was the relevant time period. While counsel could have learned about appellant's travels on the night in question with some ease from the Palmieri statement, we view counsel's ultimate failure as negligence at worst.

In this circumstance, it is obvious that concerns related to the integrity of the trial process do not weigh in favor of exclusion. Indeed, exclusion of an exculpatory and potentially reliable alibi would distort the truth-seeking function of trial. The proposed testimony does not threaten to pollute the trial with unreliable evidence; it corroborates a written statement that the prosecution itself was content to use. The fact that no willful misconduct prevented timely disclosure of the alibi also allays fears of fabrication and untruthfulness.

The prosecution could have received a continuance to investigate the alibi and cross-examine Ms. Fagundes about the night in question. Furthermore, the proposed testimony was not particularly scientific or technical in nature, which could have imposed a hardship on the government in preparing a cross-examination on short notice. Given the unintentional nature of the violation in this case, we see no threat to the trial process as a whole.

Undoubtedly the interest in the fair and efficient administration of justice is burdened by the introduction of a new defense theory after the government has closed its evidence. Alternative remedies exist, however, which adequately and appropriately address fairness and efficiency. Rhode Island Rule 16 does not limit trial judges to exclusion as the only sanction for a violation of its discovery rules. It lists less severe remedies such as requiring the offending party to reveal the discovery or inspection, granting a continuance, or entering "such other order as it deems appropriate." R.I.Sup.Ct.R.Crim.P. 16(i).

Given the important nature of the proposed testimony to the defendant, and the nonwillful character of the offense, we find that concerns over fairness and efficiency are not sufficiently weighty to justify the denial of appellant's Sixth Amendment rights. Indeed, the trial court's concern over fairness and efficiency seems less credible when the prosecution itself was willing to have the evidence admitted. This is one of those cases in which a less severe sanction than exclusion of a witness was "adequate and appropriate." Taylor, 484 U.S. at 413, 108 S.Ct. at 655.

Although we have found that error of constitutional magnitude infected this case, our analysis is not over. Before a writ of habeas corpus may issue, that error must have been sufficiently prejudicial to defendant's rights to warrant habeas relief. As the Supreme Court has framed the inquiry, the error must have "had substantial or injurious effect or influence in determining the jury's verdict." Brecht v. Ahmanson, ___ U.S. ___,___, 113 S.Ct. 1710, 1714, 123 L.Ed.2d 353 (1993) (citing Kotteakos v. United States, 328 U.S. 750, 776, 66 S.Ct. 1239, 1253, 90 L.Ed. 1557 (1946)). As this standard is "grounded in the federal harmless-error rule ( 28 U.S.C. § 2111), federal courts may turn to an existing body of case law in applying it." Id. ___ U.S. ___, 113 S.Ct. at 1722.

On the record we have before us we cannot make a sufficiently appropriate determination on whether the Taylor violation in this case meets this standard. The district court is in a better position to evaluate this issue in the first instance, as the inquiry entails a determination of the exact nature and force of Ms. Fagundes' proposed testimony and an effort to place her testimony within the context of the evidence as a whole. In short, the weight of her testimony must be balanced against the weight of the inculpatory evidence in this case, which is substantial.

We therefore remand the case to the district court for a determination of this issue. The district court should hold such hearings as necessary.