MANCHESTER – The state says murder victim Edith Riley's 12-year-old daughter saw Todd Peters, 36, in her family's apartment the morning of Oct. 11, 2008, just after he fatally beat her mother and her mother's boyfriend, Timothy King, with a baseball bat.

The defense says Peters was not in Manchester when Riley and King were fatally beaten.

Opening arguments in the first-degree murder trial in Hillsborough County Superior Court yesterday followed the "view" by 16 jurors and alternates of locations related to the murder of Riley and King, including the murder scene at 168 Valley St., several other city locations and the Weare pond where a baseball bat was found.

In her opening argument, Assistant Attorney General Jacqueline Rompre said Peters killed Riley, 35, a mother of six, and King, 21, father of Riley's two youngest children, over a trivial matter.

She said that after a fight with his girlfriend in Weare, Peters went to the 168 Bell St. apartment where his son, Dominic, lived with Peters' ex-wife, Ann Marie Peters. Rompre said it was about 4 a.m. when Peters woke Dominic, who told him that he was hit in the leg by a rock thrown by King.

Rompre said Peters' response was to go to the nearby Riley-King apartment and repeatedly hit the sleeping Riley and King with a baseball bat. "He beat Edith with a bat more than 12 times," Rompre told the jurors.

She said he also hit King multiple times. Riley died that day. King lingered in a Boston hospital until Oct. 24.

Rebecca was awakened by screams and saw Peters in the apartment, Rompre said. Rebecca knew Peters because she had seen him when she was at cheerleader practice and Dominic was there for football.

Todd Peters, right, on trial for the murders of Edith Riley and Timothy King, walks with his lawyers, Tim Landry and Melissa Kowalewski, yesterday outside the Valley Street triple decker where the attack took place. (BOB LAPREE)

Peters walked past Rebecca and left the apartment, said Rompre, but the child was able to describe him and his clothing and give police a first name.

"Rebecca never wavered from her description," said Rompre.

Rompre said a man who had come to Manchester with Peters that night, but had stayed behind at 168 Bell St., told police that when Peters came back to Bell Street, he yelled: "Run."

Back in their vehicle, Peters reportedly said: "I think I just killed somebody."

Defense attorney Melissa Kowalewski said Peters wasn't even in Manchester the morning Riley and King were beaten. She said that after getting a phone call from Dominic's coach about the boy missing practices and his mother coming to games drunk, Peters talked about getting custody of the boy. Kowalewski said that precipitated an argument with Peters' girlfriend.

Weare Police were called and gave Peters a ride to Concord, said the attorney. That's where he was with an old friend while Riley and King were being beaten, she said.

She described the neighborhood where the killings occurred as crowded and incestuous, a place where everyone knew everyone else's business and gossiped about it.

"They lied. They changed their stories. They blamed Todd.. . .They changed their stories to protect themselves and their own," Kowalewski said.

She said two searches of a Weare pond by police, dogs and conservation officers found no bat. But four days after the fatal beatings, a conservation officer saw a bat sticking out of the water a few feet from shore.

"It was planted there," said Kowalewski.

She said there is no forensic evidence tying Peters to the murder. She said there was no blood on any part of the vehicle Peters would have touched, no blood on his clothing, his shoes, his hands or the ring he was wearing.

Testimony in the trial is set to begin this morning at 9 a.m.