The state Appellate Court has overturned the conviction of George M. Leniart for the 1996 kidnapping, sexual assault and murder of Montville teenager April Dawn Pennington, a case that was brought to trial in 2010 even though the victim's body has never been recovered.

Appellate judges Michael R. Sheldon, Eliot D. Prescott and Joseph P. Flynn wrote in the lengthy decision that the trial judge, Barbara Bailey Jongbloed, should have allowed the defense to introduce a videotape interview of a key witness — Patrick J. Allain — and improperly excluded defense testimony from an expert on the reliability of jailhouse informant testimony.

The court remanded the case for a new trial, or sent it back to New London Superior Court to be tried again.

The decision does not mean that Leniart, 50, who is serving a sentence of life without the possibility of parole, would immediately be retried or released from the Cheshire Correctional Institution.

Legal experts said both sides are likely to petition the state Supreme Court to take the case and that a final decision would be years away.

Leniart could ask to be released on bond while the appeal is pending. He would be required to appear before Jongbloed, the trial judge, with such a request.

Lauren Weisfeld, chief of legal services for the Office of the Public Defender, had argued the appeal in October, citing several reasons, including the issue of "corpus delecti," or lack of concrete evidence of the crime due to the lack of a body. Reached by phone on Monday afternoon, she declined to comment.

Attorney Norman A. Pattis, who had tried the case, also could not immediately be reached.

Senior Assistant State's Attorney Stephen M. Carney, who had prosecuted the case with retired prosecutor John P. Gravalec-Pannone, said the state would be attempting to contact the victim's family with the news.

"We need to take a careful look at the decision and see what the state's next action will be," Carney said.

The appellate judges wrote that the judge should have allowed the jury to view a recording of a state police interview with Patrick "PJ" Allain, a classmate of 15-year-old Pennington who was a key witness for the state. Allain testified at the trial that he and Leniart had picked up Pennington that night and sexually assaulted her in Leniart's pickup truck. Allain testified that when Leniart dropped him off at home, the girl was still in the truck. He said Leniart told him the next day that he had killed April and disposed of her body.

The recording was a pretest that Allain had taken prior to a polygraph exam. Though polygraphs are inadmissible in court, the defense argued the interview conducted with state police before the polygraph was administered would have helped the jury assess Allain's credibility.

During the interview, state police detective Timothy Madden told Allain, who had his own legal problems, that the polygraph would determine whether he was going help the state get the "big fish'' in the case, and possibly receive a slap on the wrist, or whether he would be fully prosecuted.

The video tends to show the "subtle but significant pressure placed on Allain by law enforcement through the means of the specific factual context in which the pretest interview occurred," the court wrote.

"No amount of generic questioning of Allain on cross-examination, without clarifying this important context, would show the precise degree, nature, and effect of both the inducements and pressure on Allain to inculpate the defendant that the videotape reveals," the decision says.

The appeals court also wrote that the trial judge should have allowed the defense to elicit testimony from Loyola Law School Professor Alexandra Natapoff, an expert on jailhouse informants.

The state relied on four convicted felons to make its case against Leniart. In ruling it would not be allowed, Jongbloed had said the subject matter is not outside the "ken," or common knowledge, of the jury and that the court would give the defense a wide latitude to discredit the witnesses during cross examination.

The Appellate judges wrote that Natapoff could have aided the jury in evaluating the credibility of the informants.

k.florin@theday.com