BANGOR, Maine — The man convicted of stabbing to death a 19-year-old woman nearly two years ago in a cluttered shack on the Bangor waterfront is seeking a new trial based on a jailhouse conversation with a fellow inmate.

In a motion filed Tuesday at the Penobscot Judicial Center, attorneys for Colin Koehler, 36, of Bangor argued that John Whitney was with the victim, Holly Boutilier, 19, of Old Town shortly before the time of her death.

Whitney also “claims to have witnessed the victim leave his company, walking away with two other men, neither of whom were the defendant,” the motion said. “The three were walking toward Sea Dog Microbrewery and Restaurant, which is located near the waterfront trail along which the victim’s body was discovered.”

That contradicts the testimony of Justin Ptaszynski, 29, of Bangor, who told the jury at Koehler’s murder trial last fall that he saw the defendant stab Boutilier to death. Ptaszynski, who is serving six years in prison, also identified the murder weapon as the one Koehler wielded the afternoon of the slaying, Saturday, Aug. 8, 2009.

Koehler denied killing Boutilier. He testified that he was never at the shack where Boutilier’s bloody body was found on Sunday, Aug. 9, 2009. Koehler told jurors he was at the 3-on-3 Charity Basketball Jam that was held the day before in the public parking lot on the Bangor waterfront.

The motion for a new trial was filed by Richard Hartley of Bangor and Peter Cyr of Portland one day before Koehler was scheduled to be sentenced for murder.

Whitney’s age, hometown and why he was incarcerated at the Penobscot County Jail were not included in the motion.

The motion also said that Whitney claims to have spoken with an investigator two days after Boutilier died. The defense team was not informed of the interview, a violation of discovery rules, the motion argued.

The Maine Attorney General’s Office had not filed a reply to the motion as of Tuesday afternoon. Assistant Attorney General Andrew Benson, who prosecuted the case, is expected to oppose the motion.

Koehler remained Tuesday at the Penobscot County Jail, where he has been held since his arrest Aug. 11, 2009.

A new sentencing date most likely will not be set until Superior Court Justice William Anderson, who presided at the trial, rules on the motion.

Reprinted with permission from the Bangor Daily News.