Defendant Nathan Eldredge repeatedly struck his victim with a billy club while he slept and, seeing that he was still alive, suffocated him with plastic bags, a jury was told Tuesday in Stillwater.

Eldredge then dragged Nils Johnson's body into a closet, hid it beneath cardboard boxes and a sleeping bag, and left the apartment in Oak Park Heights only to later return with a young woman, prosecutor Fred Fink said in opening the first-degree murder trial in Washington County District Court.

"Who would kill someone so he could have sex with his girlfriend?" Fink said to the jury.

Eldredge, 25, choosing to represent himself, sat alone at the defense table. He declined to make an opening statement and in a barely audible voice declined to cross-examine any of six witnesses that Fink and his co-prosecutor, Siv Yurichuk, called to the stand.

Johnson, 39, was found dead in April 2015 in his two-bedroom apartment after an investigating police officer detected a strong offensive odor.

Johnson, who had been diagnosed as paranoid schizophrenic, worked as a cook at McDonald's in Oak Park Heights for two years. He had allowed Eldredge to stay at his apartment.

Police found Johnson's body seated upright, his hands bound with black tape and a plastic bag sealed over his head.

Fingerprint and DNA testing from the Minnesota Bureau of Criminal Apprehension proved conclusively that Eldredge committed the murder, Fink told the jury.

Two neighbors testified Tuesday that they heard screams from a man in their apartment building at 14655 62nd St., where Johnson lived alone. Olga LaGrave said she was awakened early that morning when she heard a scream through the wall.

"It sounded like someone was waking up from a nightmare or had a heart attack and was in a lot of pain," she said.

Neighbor Brian Bursch, who also heard a scream, said he had known Johnson for about 15 years. "He was simple in intellect but very open and friendly to everyone," Bursch said.

Eldredge's former girlfriend, Destiny Phillips, testified that he brought her to the apartment in Oak Park Heights, telling her it belonged to a friend who was gone overnight. She said he was driving a small white pickup, the kind of vehicle that other witnesses said was owned by Johnson.

Phillips said she saw handcuffs and a billy club in the bedroom. They had sex in bed that night and were starting to have sex on the living room floor the next morning when they heard knocks on the door, first from Johnson's mother and then from police inquiring about Johnson's whereabouts.

Phillips said that a few days later, after she and Eldredge saw several police vehicles at the apartment, they went to a restaurant.

"He just proceeded to walk away and that was the last time I ever saw him," she said.

Eldredge, who has family in Tennessee, later was arrested in Cook County, Ill. He initially was charged with second-degree murder with intent, but in September a grand jury returned an indictment for first-degree murder.

Eldredge remains in custody in the Washington County jail. The trial continues this week.

Kevin Giles • 651-925-5037