Though much of the evidence collected in the Lori Hacking (search) disappearance does not necessarily point to murder, it could still help police solve the case, the head of Utah's crime lab said Thursday.

Maj. Stuart Smith, chief of the Utah Bureau of Forensic Services (search) and a former state police investigator himself, said police were thorough in collecting and preserving evidence.

"The police followed good procedures," Smith said. "That will all bear fruit later when there's something to compare it to."

A significant portion of the evidence consists of everyday items taken from the Salt Lake City apartment Hacking shared with her husband, Mark Hacking (search). None of them show any obvious connection to foul play, Smith said.

Still, the scissors, knives, tape, rope and other household objects removed from the apartment may come in handy later when investigators need to match clues unearthed from other locations, including the municipal landfill police have been combing with cadaver-sniffing dogs.

Mark Hacking, 28, reported his five-weeks-pregnant wife missing July 19. Since then, he has been caught in a web of lies that have led police to label him a "person of interest" in the case. No one, including Mark Hacking, has been called a "suspect."

Mark Hacking has been in a psychiatric hospital since the day after his 27-year-old wife disappeared.

The family of Lori Hacking said they were holding a day of fasting and prayer Friday and invited those who wanted to help to join them.

Police, who have spent four nights at the landfill using a backhoe to burrow 15 feet deep into a huge mound of garbage and dirt, said they did not plan to return with the dogs Thursday night.

"The dogs need a break," said Detective Phil Eslinger. He was uncertain how long the dogs needed to rest, but said their handlers would know when the animals were up to the job again.

The landfill search may be a long shot, but police cannot afford to overlook tips that led them to cordoning off a sprawling area used to deposit a day's layer of trash, Smith said.

One tip came from a neighbor of the Hackings who said someone may have used his plastic trash bin, left on the street, to dispose of a dead body.

The neighbor found a foul "protein-rich" liquid in the bottom of the barrel after collection rounds the day Lori Hacking, a stock trader's assistant, disappeared.

The landfill search is nothing if not daunting.

"A car could be in there and you might not find it," Eslinger said. "This is very much like looking for a needle in a haystack."

The state crime lab has a six-week backlog of samples from criminal cases awaiting testing. Smith said he was reluctant to drop everything for the Hacking case until police can identify their most important pieces of evidence.

A single DNA (search) analysis can cost $700, he said. That makes it important for investigators to decide which pieces of evidence require a full chemical or DNA analysis. It can take several weeks to fully analyze a single piece of evidence.

The fact that Lori Hacking was an adopted daughter is one factor that can complicate DNA testing, he said.

Smith left the impression police have yet to collect evidence from her apartment or elsewhere that would obviously point to foul play in Lori Hacking's disappearance. But he wouldn't discuss the condition of an old mattress police recovered from a trash bin in the Hackings' neighborhood.

Police said Mark Hacking, a hospital orderly, was at a store buying a new mattress shortly before telling police his wife hadn't returned from an early-morning jog July 19.

His credibility came under scrutiny since it was revealed he had been lying to his wife, family and police about having been accepted to medical school at the University of North Carolina. Hacking had also not graduated from college, as he told friends and relatives.

Police said Hacking lived a life of various lies for at least four of the five years he has been married. He has been at a psychiatric hospital since he was found running outdoors naked the night after the search began.

The University of Utah has posted Hacking's job, health care assistant, which starts at $8.42 an hour and requires work at odd hours. Health care assistants work under the direction of nurses and support patients' basic needs, the job description says.

The University accepted Hacking's resignation July 23, television station KUTV reported.

The Associated Press contributed to this report.