The investigation into the disappearance of Nancy Guthrie has uncovered several notable pieces of evidence as authorities in Arizona continue to search for the mother of “Today” show co-host Savannah Guthrie.
Investigators believe Nancy Guthrie, 84, was forcibly taken from her Tucson home in the middle of the night before being reported missing Feb. 1. Pima County Sheriff Chris Nanos confirmed that all of Guthrie’s family members and their spouses have been cleared as possible suspects.
While the FBI and the Pima County Sheriff’s Department haven’t revealed everything they’ve uncovered in the weekslong investigation, officials have disclosed some details about the clues and potential evidence in the case.
Here’s what we know about the evidence so far:
What the suspect wore in Nancy Guthrie’s home security video
Investigators believe the clothing and face mask worn by a suspect in home security video footage may have been bought at Walmart, either at a brick-and-mortar store or online, Sheriff Chris Nanos told CBS News.
The sheriff’s department noted, however, that the clothing is not exclusively available from Walmart.
Walmart sells a mask that looks very similar to the mask worn by the man in the doorbell camera video. It is believed to be black, but it looks lighter in the footage because of the Nest camera’s infrared technology, according to Nanos.
Pima County Sheriff’s Department via Reuters 
The FBI said the suspect was also carrying a black, 25-liter Ozark Trail Hiker Pack backpack in the video. CBS News first reported that the backpack is sold exclusively at Walmart.
Nanos called the backpack “one of the most promising leads” in the case.
Investigators have been reviewing surveillance video footage from local Walmart locations, Nanos said. The company has provided authorities with records of all Ozark Trail Hiker purchases from the past several months, Nanos said.
FBI 
A spokesperson for Walmart declined to comment on the case.
DNA recovered from Nancy Guthrie’s home
The sheriff’s department said DNA that didn’t belong to Nancy Guthrie or those in close contact with her was collected from her property, and investigators say it is being analyzed. The department did not disclose where on the property the DNA was found.
Sources close to the investigation told CBS News there’s concern that the DNA found at the home may not yield a useable profile for comparison in databases. The Pima County Sheriff’s Department said its contracted lab in Florida is continuing to analyze the samples and has not reached a conclusion on whether they’re usable.
DNA profiles can submitted to the national DNA database maintained by the FBI, known as CoDIS, or Combined DNA Index System, which contains DNA profiles of individuals with a previous arrest for certain crimes who had supplied a DNA sample that put him into the system.
Investigators can also search commercial genealogy databases with the same DNA profile for a possible match, a federal law enforcement source told CBS News. Those databases are completely different from the CoDIS national database.
Earlier, a DNA profile of an unknown male was recovered from a glove that investigators found about 2 miles Guthrie’s home, and which appeared to match the ones seen on the suspect in Guthrie’s Nest camera video.
However, investigators eventually traced the gloves back to a local restaurant worker who has no connection to the case, the Pima County Sheriff’s Department said.
Video footage recovered from Nancy Guthrie’s security camera
The FBI publicly shared several excerpts of footage from Guthrie’s Nest camera on Feb. 10, saying that the previously inaccessible video from the morning of Guthrie’s disappearance was recovered from “residual data located in backend systems.”
The FBI described the suspect in the video as a male who is about 5 feet, 9 inches to 5 feet, 10 inches tall with an average build.
In one video clip, the suspect approaches the front door and raises a gloved hand to the camera outside the door before turning back. In a separate clip, the masked suspect faces the camera holding a flashlight in their mouth before covering the camera lens with some vegetation.
Nanos previously told reporters at a news conference that the doorbell camera at Guthrie’s home was disconnected at approximately 1:47 a.m. on Feb. 1.
At around 2:12 a.m., one of the home’s cameras detected what the system classified as a person, but Nanos said video footage wasn’t available.
Google, which makes Nest cameras, previously told CBS News it was assisting with the investigation.
Possible data from Nancy Guthrie’s pacemaker
In another electronic data point, officials said Nancy Guthrie’s pacemaker app showed a disconnect from her phone at 2:28 a.m. on Feb. 1.
Law enforcement sources told CBS News that one of the high-tech tools investigators have deployed in its search is a tracking device known as a “signal sniffer” in an effort to detect possible signals from her heart pacemaker.
Investigators, mounting the device on a helicopter flying slow and low, have tried to determine if Guthrie’s pacemaker is emitting any detectable signals that could be used to help target her whereabouts, according to the sources.
The device frequently used in missing person cases is a portable radio detection device used to detect specific low-powered electronic signals such as those from a pacemaker.
Apparent ransom note demands payment in bitcoin
An apparent ransom note demanding payment in bitcoin was received by CBS Tucson affiliate KOLD-TV on Feb. 2, the day after investigators believe Guthrie was taken.
While authorities haven’t said whether the note is credible, the FBI said it was taking it seriously.
The note included two deadlines, for Feb. 5 and for Feb. 9.
Separately, a Southern California man has been charged in federal court with allegedly making a fake ransom demand via text messages on Feb. 4. Authorities believe he was trying to take advantage of the situation for monetary gain.
Several homes searched
Law enforcement agencies have searched at least two homes in connection with the investigation, but details are scant. The first of those searches took place in Rio Rico, Arizona, south of Tucson, on Feb. 10.
Authorities said they were questioning a person of interest, and a man who gave his name as Carlos later said he was detained by officers and then released. He said he didn’t know why law enforcement thought he had anything to do with it.
“I didn’t do anything,” he said, “I’m innocent.”
Another surge of law enforcement activity took place the night of Feb. 13 about 2 miles from Nancy Guthrie’s home. The sheriff said it was based on “a lead that led to a search warrant.” Several people were apparently questioned but no arrests were made.
Authorities did not release details on what led to that search or what, if anything, may have been found.