Investigators say they just had to give the cadaver dogs a rest.
Police say they have found nothing of consequence in their search of the county landfill, but from what reporter Ben Winslow of CBS radio affiliate KSL-AM has seen, it appears they are narrowing down their search.
"We'll be there until we're convinced that we've completely and thoroughly searched it," said Detective Kevin Joiner.
Joiner would not say whether police are looking in the landfill for a body.
"The whole focus of the investigation at this point still is to find Lori, wherever that may be," he told Winslow.
Hacking, five weeks pregnant, was reported missing by her husband 11 days ago. Since then, his family has learned that he lied about graduating from the University of Utah and being accepted at medical school in North Carolina. There are indications his wife found out about the deception shortly before she disappeared.
The Hackings' neighbor, Devan Hite, asked police to collect and examine a reddish-brown fluid he found in bottom of his garbage can the day after Lori Hacking disappeared.
"I thought about the possibility that Lori was killed and that part of her was disposed of in the garbage can, but I don't know," he told CBS News Correspondent Lee Cowan.
Police won't say if that was the tip that led them to search the Salt Lake landfill, but they're hinting strongly that something is there.
"There's substantial lead, otherwise we wouldn't be spending the time and resources to be out there," Detective Phil Eslinger said.
Sources say police did find blood inside Lori Hacking's apartment consistent with a stabbing, and it appeared as if someone had tried to wash that evidence away.
"There's always little nooks and crannies where blood can go hide, and those nooks and crannies are what we're looking for," said Jay Henry of the Utah Bureau of Forensic Services.
A mattress removed from the Salt Lake City apartment by police last week had a red stain either on it or on its cover.
The Deseret News reported that a knife with blood and hair was also one of the items seized, but the results of forensic tests on any evidence collected could be "weeks to months" away, a detective said.
Mark Hacking, 28, has come under scrutiny for buying a new mattress shortly before reporting his wife missing, as well as lying to his wife, family and police about being accepted to medical school in North Carolina, where the couple planned to move this week.
"We learned a lot of things in his life that are not true," Detective Dwayne Baird said. "Medical school was the pinnacle of that deception."
"He worked harder at maintaining his lies and deceptions than others do at earning a living," he added.
The nightshift hospital orderly was checked into a psychiatric ward by his family after being found outside, naked, a night after the search for his wife began.
The parents of Lori and Mark Hacking have asked the community to observe Friday as a day of fasting and prayer in hopes of aiding the search that will find Lori.