SKOWHEGAN, Maine — The attorney for convicted killer Shannon Atwood of Canaan has asked for a new trial, stating that Justice Nancy Mills, who ruled in the case, was “unduly tainted by prejudicial publicity and prior knowledge.”

The attorney contends that Mills knew a previous victim of Atwood’s — she was Mills’ hairdresser — and that Mills used Atwood’s conviction in that case as part of the information she based her guilty verdict on earlier this year.

“This is a touchy matter,” Attorney John Alsop said Wednesday. “But I must do my duty to my client.”

On July 2, Atwood was found guilty of murdering Cheryl Murdoch, 38, in the summer of 2006 and leaving her bludgeoned body in the Burrill woods of Canaan just a few miles from the home the couple shared on Route 23.

Police found Murdoch’s body on Aug. 11, 2006. The charge that he also murdered his estranged wife, Shirley Moon Atwood, 35, was dropped in November 2007. During the Murdoch murder investigation, it was discovered that Moon-Atwood had been missing since early 2006.

At Somerset County Superior Court in Skowhegan last July, Mills heard 49 witnesses over five days in Atwood’s case, which was built largely on circumstantial evidence. After finding Atwood guilty, Mills deferred sentencing until a state-requested forensic psychological examination is completed. A conviction could result in a term of 25 years to life.

Alsop said Wednesday that “we are walking a fine line here. We are not suggesting that Justice Mills did anything improper.” But Alsop also said that it was unclear how much weight Mills put on her knowledge of Atwood’s previous conviction. “We don’t really know and we need to review the situation,” he said.

In his motion, Alsop states that during the trial, the Bangor Daily News and the Central Maine Morning Sentinel published stories about one of Atwood’s previous victims, Jen Nickerson Steward.

Fifteen years ago, Atwood attacked and brutally beat Steward when she tried to break off their relationship. The two were living in Bingham at the time.

Atwood was convicted of aggravated assault and sentenced to six years in prison. All but three years were suspended, and Atwood ended up serving 14 months in prison.

Before she rendered her verdict in Atwood’s murder trial this year, Alsop said Mills held an attorney’s conference in her chambers and said that she had read the story and realized that Steward was her hairdresser. “Mills said she was reminded when she read the paper and stopped reading the paper when she made that connection,” Alsop’s motion states.

Just moments later, when she rendered the guilty verdict, Mills referred to Atwood’s statements to police on Aug. 10, 2006, when he was interviewed before his arrest.

“I’ve been to f….. prison,” Atwood said. “I know you guys know that, and I’ve been back out now for almost 12 years. I’m pretty proud of that and I ain’t going back.”

The motion states that since Mills referenced the killer’s prior criminal involvement as part of her decision regarding a verdict, it was incorrect and prejudicial.

“This was a close and difficult case,” Alsop said, and be-cause Mills appears to have relied on the statement as “a significant building block upon which the conviction is based,” he asked for Mills to reconsider her verdict or order a new trial.

“These facts do certainly create the appearance of a verdict unduly tainted by prejudicial publicity and prior knowledge,” the motion states.

Alsop said Wednesday that if the same circumstance had come to light regarding a juror, he would have made the same motion.

“This is a serious case and a serious conviction,” Alsop said. “Obviously we need to be very careful.”

Alsop filed the motion in August, but a hearing has been delayed while Mills recovers from a medical condition.