Investigators probing the abduction of 84-year-old Nancy Guthrie say clothing and gear worn by the masked suspect in the now-infamous doorbell footage were likely purchased at Walmart — a development authorities describe as one of the most significant leads in the case so far.

Pima County Sheriff Chris Nanos told CBS News that detectives believe the clothing and face mask seen in the surveillance video were sold by the retail giant. The suspect’s black Ozark Trail Hiker backpack — clearly visible in the footage — is sold exclusively at Walmart.

Nanos said investigators are working to identify the exact brands associated with the items. Authorities are also trying to determine whether the gear was purchased online or at a physical store, either in Arizona or elsewhere. Detectives have spent days reviewing surveillance footage from local Walmart locations in an effort to trace the buyer.

According to CBS News, Walmart has provided records of recent Ozark Trail Hiker backpack purchases, including both in-store and online transactions, not only in Tucson but in surrounding areas as well. A Walmart spokesperson declined to comment on the investigation.

The backpack has become a focal point for investigators as the search for Guthrie enters its third week.

The 84-year-old, who is the mother of “Today” show co-host Savannah Guthrie, was abducted from her Tucson-area home in the Catalina Foothills during the early morning hours of February 1. Authorities have said there were signs of forced entry and blood evidence found at the residence.

Federal investigators have also concentrated on the suspect’s mask. Though it appears lighter in the doorbell footage, authorities believe that is due to the infrared capabilities of the Nest camera and that the mask itself is black.

The FBI has released images of the suspect, describing him as a male of average build, approximately 5 feet 9 inches to 5 feet 10 inches tall.

Forensic developments may also be narrowing the field. Over the weekend, the FBI confirmed that a black glove recovered near Guthrie’s home appears to match the gloves worn by the suspect in the surveillance video.

The bureau said preliminary DNA results were received Saturday and identified an unknown male profile. Once quality control procedures are completed, the DNA profile is expected to be entered into CODIS, the FBI’s national DNA database, which could generate a match if the individual has a prior record.