Salt Lake City ? A man accused of killing his wife after she found out he lied about getting into medical school pleaded guilty to murder Friday, making a simple declaration to the judge: “I intentionally shot Lori Hacking in the head with a .22 rifle.”

Prosecutors say Mark Hacking carried out the attack while his wife slept last July and then threw the body of the 27-year-old woman in a trash bin. Volunteers scouring a landfill found her decomposed remains about three months later.

The victim’s father, Eraldo Soares, said hearing Hacking admit guilt in court “was just like a knife going right through my heart. I could not imagine that he could do that to Lori.”

Prosecutors said the sentencing range would be from six years to life for Hacking, who appeared in court Friday with his hands cuffed behind his back and with a look of resignation. Prosecutors said they would push for the maximum sentence, and the possibility of Hacking getting the low end of the sentencing range was remote. Sentencing was scheduled for June 6.

“Under this charge, there is no possibility of probation. He will be going to prison,” prosecutor Bob Stott said. “He pleaded guilty to murder, and that’s what we were looking for. We were looking for the life sentence.”

Hacking, a 28-year-old hospital orderly, pleaded guilty to first-degree murder. He also was charged with obstructing justice by disposing of the body, the gun and a bloody mattress, but those charges were dropped as part of Friday’s deal.

Prosecutors were unable to determine if Lori Hacking was five weeks’ pregnant, as she had told friends. That meant the husband could not be charged with a capital crime.

Defense attorney Gil Athay repeated in a Friday interview with Salt Lake television station KUTV his earlier claim that Hacking might have suffered “brain trauma” after a fall from a rooftop.

“He fell in a roofing accident some years ago and suffered some substantial brain trauma,” Athay said, adding that he planned to present that evidence at sentencing. “I think it plays heavily in where this case is.”

Lori Hacking’s colleagues at a Wells Fargo brokerage house have said she broke down sobbing after learning of her husband’s deception. She became aware of the lies after making calls to school administrators in North Carolina, where Hacking claimed he was enrolled for medical school. Hacking also had lied about graduating from the University of Utah.

Mark Hacking entered his plea after his lawyer showed no sign of preparing for a trial. Athay filed no motions, asked for none of the usual hearings that precede trials and contacted no prosecution witnesses — leading many to believe a plea deal was in the works.

That became more apparent when Judge Denise Lindberg scheduled another murder trial for the time Monday when she was to preside over Hacking’s trial.

Hacking had reported his wife missing to police, saying she had not returned from a morning jog in a Salt Lake City park.

The news prompted a weeklong search for the former stockbroker’s assistant by thousands of volunteers — a search that echoed another sensational Salt Lake City crime, the kidnapping of Elizabeth Smart from her bedroom.

Hacking was in a psychiatric hospital after suffering a breakdown when he confessed to his brothers that he killed his wife using a .22-caliber gun.