Raleigh, N.C. — The North Carolina Supreme Court on Friday turned down convicted murderer Mike Peterson's appeal for a new trial.

Peterson, 63, was convicted Oct. 10, 2003, of first-degree murder in the 2001 beating death of his wife, Nortel Networks executive Kathleen Peterson. She was found dead at the bottom of a staircase in their Durham mansion.

Mike Peterson has maintained his wife fell down the stairs after consuming alcohol with her medication.

"For the major issues, this is the end of the line. It's one of the reasons I am so disappointed by it," said Tom Maher, Mike Peterson's attorney. "One of the feelings (I have) is of real deep sadness. Mike might not ever get out. I do care about him."

Justices turned down three arguments for a new trial, including evidence in the death of Elizabeth Ratliff, a longtime Peterson family friend. Ratliff was found dead at the bottom of a staircase in Germany in 1985.

Other issues Peterson appealed included the court's admission of evidence seized by use of an invalid search warrant and allegedly inflammatory statements made during prosecutor Freda Black's closing argument in the case.

"We conclude that, because the state presented overwhelming evidence of defendant's guilt, independent and separate from the tainted evidence, no reversible error occurred," Justice Edward Brady wrote for the court.

The North Carolina Court of Appeals in September rejected Peterson's arguments that his five-month trial was filled with inflammatory, irrelevant evidence, such as Ratliff's death and testimony of a male escort, and judicial mistakes.

When he broke the news of the Supreme Court decision to Peterson, Maher said he was silent for a couple of seconds. "Then (he was) back to the Mike we all know," Maher said.

Friend Kerry Sutton said she spoke with Peterson from prison after the decision.

"Mostly he said, 'I'm fine. I'm innocent. I know what happened. I'm going to keep fighting. I'm not done yet,'" Sutton said.

Maher said Peterson could ask the U.S. Supreme Court to review the appeal, but few such cases are heard. He also could opt to appeal again to the state on other motions for relief, such as ineffective counsel, Maher said.

Jay Trehy, an attorney for Kathleen Peterson's daughter, Caitlin Atwater, said the family was "delighted, but not surprised" by the Supreme Court ruling.

Lori Campell, one of Kathleen Peterson's sisters, thanked prosecutors in the state Attorney General's Office and the Durham County District Attorney's Office for pursuing the case until the end.

"My sister did suffer a pretty horrible death," Campbell said. "(We're) grateful Michael did not get away with murder. May my sister rest in peace."

Meanwhile, the mansion at 1810 Cedar Street where Kathleen Peterson died has been on the market for several months.

The owners of the 9,200-square-foot home, who bought the property three years ago for $640,000, have reduced their asking price from $2.1 million to $1.7 million.