A high school teacher's husband has admitted killing his wife's teenage lover, her former student, but it will be up to a jury to decide if it was premeditation, the heat of passion or an accident.

Eric McLean, 33, is charged in last year's killing of 18-year-old Sean Powell with a high-powered rifle outside the modest home McLean shared with his wife, Erin, and their two young sons. Jury selection began Wednesday.

McLean faces up to life in prison with the possibility of parole — a minimum 51 years — if convicted of first-degree murder; prosecutors aren't seeking the death penalty.

McLean's attorney Bruce Poston will be arguing for conviction on a lesser charge, with punishment ranging from a few years in prison to probation.

In a jailhouse interview with NBC's "Today Show" 10 days after the shooting, McLean acknowledged he shot Powell, though he claimed it was an accident. His lawyer wouldn't let him elaborate.

McLean said he "had been in denial for a long time" but concluded his wife, then 29, was having an affair with Powell.

"I just couldn't leave her," he said. "Because I love her!"

Powell and Erin McLean met the previous fall when she was practice-teaching English at West High School. He dropped out of school but planned to get an equivalency degree, his adoptive parents said.

His mother, Scarlett Powell, eventually issued a statement calling Erin McLean a "master manipulator" who victimized her former student.

Eric McLean was supporting his family by delivering pizzas while trying to finish his college degree to become a band director and music teacher. He told authorities he suspected for several weeks that his wife of 11 years was having an affair with Sean Powell.

McLean said his oldest son, Eric Jr., now 12, told him he saw Powell and his mother holding hands and kissing. The husband told investigators he tried to work things out with Erin, welcoming Powell into their home and letting him sleep over on a couch.

However, when McLean came home March 10, 2007, he found Powell there and demanded the teenager leave. Powell refused and McLean called 911. He reported an intruder, "some guy who's stalking my wife."

After a few moments, Powell apparently backed down and McLean told the dispatcher the intruder was leaving.

Seven minutes later, Erin McLean called 911 and screamed, "My husband just killed someone. ... Please come. Hurry! Hurry!"

Powell hadn't gone far. He was sitting in his car in front of the house, smoking a cigarette, when Eric McLean came up to him with a rifle he'd gotten from his pickup truck.

McLean claims he got the weapon a few weeks before to kill himself. Instead, he used it to fire one blast to Powell's head. An autopsy found a defensive wound on Powell's hand.

McLean fled in his truck to the high school where his wife had taught. Then he walked along a set of railroad tracks until he was apprehended the next day about six miles away.

Prosecutors contend the facts point to premeditated murder. Poston says what happened in those seven minutes between the 911 calls shows an act in the heat of passion, part of his argument for conviction on a lesser count like voluntary manslaughter.

"It can be spun a different way," Poston said. "You can show how pathetic he is. He has to call the police to get an 18-year-old out of his house? Who is in control here? We are dealing with an 18-year-old who is mature beyond his years and a 31-year-old that is the biggest wuss in the world."

Erin McLean fled with her sons to Nashville, where police said she attempted suicide.

Where she and the children are now isn't clear. Her Nashville attorney, Gary Blackburn, did not immediately return a call from on Tuesday.

Erin McLean did not attend the couple's divorce proceedings in February. She is listed as a possible witness against her former husband.

Assistant District Attorney Bill Crabtree, who also did not immediately return a call seeking comment, failed to get a first-degree murder indictment the first time the case went before a grand jury. The panel instead returned a second-degree murder charge carrying a 25-year maximum sentence. A second grand jury in December agreed to hand up the first-degree charge to prosecutors.

"It tells me they are desperate to do anything to put this guy in prison for as long as possible," Poston said.