Lori Hacking's body has not been found, despite numerous searches of a local landfill.
The charge against Mark Hacking carries a possible penalty of five years to life in prison.
Hacking confessed to his brothers that early on July 19 he walked into the couple's bedroom and fired a single shot in his wife's head with a .22-caliber rifle, according to a probable cause statement released Monday.
He then wrapped her body in garbage bags and placed it in a trash bin about 2 a.m. that day, the statement said. He allegedly disposed of the gun in another bin.
Hacking was also charged with three counts of obstructing justice; each carries a possible one to 15 years in prison.
Salt Lake County District Attorney David Yocom had the option of filing a count of aggravated murder against Hacking, which carries the death penalty.
But the absence of Lori Hacking's body would have made that difficult to prove. Yocom also did not file a homicide charge to account for Lori Hacking's unborn baby.
The woman told friends just before her disappearance that she was five weeks pregnant, relying on a home pregnancy test. Without a body, police have not been able to confirm she was pregnant. She apparently did not visit a doctor.
Police have said they are confident in their case against the husband even without a body.
Mark Hacking, 28, reported his 27-year-old wife missing July 19. He said she had gone jogging at a downtown park and never showed up for work. But police later uncovered a series of lies by the husband, and said his wife likely never went jogging that morning.
The night she was reported missing, police found Mark Hacking naked outside a hotel near the couple's apartment. He was checked into a psychiatric ward by his family, where he stayed for more than a week before his arrest.
His two older brothers, Scott and Lance, talked with him at the hospital July 24 and later told police that he told them he killed his wife as she slept.
Since the day his wife was reported missing, Mark Hacking's credibility has eroded amid revelations that he lied to his family about enrolling at medical school in North Carolina and about graduating from the University of Utah.
Despite the lies, police believe the statements attributed to Hacking in the probable cause document are credible. "Everything corroborates the truth of this statement," Yocom said.
The Friday before she was reported missing, Lori Hacking left work stunned and sobbing. Her co-workers said she had been making some arrangements with the medical school, and that they believe an administrator was calling back to say Mark Hacking wasn't enrolled there.
His father believes Mark Hacking "just snapped" and killed his wife after she learned he had been lying for years about his education and career plans.
Hacking was arrested Aug. 2. An affidavit filed by police says investigators found human blood on a knife in the couple's bedroom and on the headboard and bed rail. The blood also matched traces of blood found in Lori Hacking's car, police allege.