Nancy Guthrie live updates: Officials not ruling out possibility that multiple people were involved

The Pima County Sheriff's Department provided a small update Saturday on their investigation into the case.

Detectives and agents were back in the neighborhood canvassing for clues, according to the sheriff's office.

Investigators noted that "Detectives and agents have collected multiple gloves from the area, and analysis is part of the investigation."

"Specific details about these pieces of evidence will not be shared publicly, as this remains an active investigation," the sheriff's office said in a statement.

The lack of recent progress in the probe into Savannah Guthrie's mother's kidnapping may mean that investigators soon scale back their resources, sources with knowledge of the case told ABC News Friday.

Nearly three weeks after Nancy Guthrie vanished, investigators are finding their best leads are so far coming up empty.

Partial DNA recovered at the home is, for the moment, unidentified; technology companies and the FBI have recovered no additional video from her home security system; and investigators have been unable to associate a vehicle with her abduction, law enforcement sources told ABC News.

Right now, there are 400 investigators assigned to the case operating 24/7, the sheriff's department has said. Given the seemingly sluggish progress, investigators believe the case would soon have to move into a new phase with fewer dedicated resources but a small task force focused on it long term, the sources said.

The Guthrie family is aware that the investigation might need to be transitioned and has been briefed on the fact that certain leads have not been panning out, the sources said.

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Investigators are not ruling out the possibility that more than one person may have been involved in Nancy Guthrie's abduction, the Pima County Sheriff's Department said Friday.

The sheriff's department said it also continues to seek information to help identify the man captured on Nancy Guthrie's doorbell video, and that investigators are reviewing surveillance video submitted by her neighbors.

A lawyer representing a convicted felon said his client and his client's mother were briefly detained as part of the Nancy Guthrie investigation.

Luke Daley, 37, and his mother, who is 77, were detained and had their house searched on Feb. 13, according to his lawyer, Chris Scileppi. Their home is about 2 miles from Guthrie's.

Chris Scileppi confirmed Daley -- who has served time in state prison on drug-related charge -- was the target of the operation by the FBI and Pima County Sheriff's Department but reiterated neither Daley nor his mother were arrested and said they have no link to Guthrie.

"Like the entire Tucson community, both Mr. Daley and his mother are hopeful that Nancy will be returned to her family unharmed," Scileppi said in a statement.

Daley was the second person detained for questioning and released after a deliveryman who identified himself as Carlos was stopped earlier in the investigation. ABC News has previously reported investigators are leaning away from both men as possible suspects.

-ABC News' Aaron Katersky