(KSL News / AP) -- Investigators returned to the Salt Lake County Landfill hoping to bring closure to a family and key evidence to prosecutors.
Last night's search of the landfill marks the second straight day crews have looked for Lori Hacking's remains, evidence the District Attorney needs to charge her husband with aggravated murder.
It's become a familiar scene for police -- the painstaking process begins as night falls. The massive landfill has been cornered off to one specific section about the size of two football fields. Cadaver dogs and search crews comb through thousands of pounds of compacted trash hoping to stumble upon the evidence they need, Lori Hacking's body.
Prosecutors need that evidence to determine if Lori was, in fact pregnant at the time of her death. That information would help determine if Mark Hacking will be charged with aggravated murder.
Thursday, the Salt Lake County District Attorney's Office filed for an extension on a deadline to formally press those charges against Mark. A judge granted that motion, saying the Salt Lake City Police Department "needs additional time to complete their investigation."
Back at the landfill police still say they haven't found anything significant. They say it could be weeks, even months before something turns up, but they are confident Lori's body will be found.
Meanwhile, the attorney for Mark Hacking, who told his brothers that he killed his wife and dumped her body in a garbage bin, plans to challenge his statements to his kin.
"Remember Mark was housed in a psychiatric unit for the period of time these brothers are claiming they spoke with him," attorney Gil Athay told a local TV station Thursday. "To me that creates a substantial issue."
He said, "mental illness, mental deficiency certainly will be an issue in this case."
Mark Hacking, 28, reported his wife, Lori, missing on July 19. He said she had gone jogging and never showed up for work. That night police found him naked outside a hotel and he was taken to a hospital and placed in the psychiatric ward.
The following Saturday -- the state's July 24 Pioneer State holiday -- his two older brothers, Scott and Lance, talked with him at the hospital. They said he told them he had killed his wife while she was sleeping.
The brothers said they passed the information along to police through an intermediary.
For years, Mark Hacking allegedly lied to his wife, family and friends about his education and career plans. Not only wasn't he enrolled at medical school, he hadn't even graduated from the University of Utah. Yet he and his wife were packing for the move to Chapel Hill, N.C.
The Friday before she was reported missing, Lori Hacking left work stunned and sobbing. Her co-workers told the AP that she had been making some arrangements at the North Carolina medical school, and that they believe an administrator was calling back to say Mark Hacking wasn't enrolled there.
His father believes Mark "just snapped" and killed his pregnant wife after she learned he had been lying for years about his education and career plans.
"I think it's clear that this whole house of cards he had built, all this deception, had come to an end. He had been found out. His wife discovered his deception and confronted him with it, and I just think he just saw his whole world collapsing and broke down," the father, Douglas Hacking, told The Associated Press.
"He just snapped, and did something there's no explanation for. That's the only way I can envision it," he said.
Scott and his father are physicians, and Lance Hacking is an electronics engineer. Douglas Hacking said he believed Mark probably felt pressured by his family's achievements.
Mark Hacking was booked into the Salt Lake County Jail Monday when officers learned that he was about to be released from the hospital.
(The Associated Press contributed to this story)