The FBI is analyzing a DNA sample collected from the Tucson home of 84-year-old Nancy Guthrie, who was abducted on February 1, according to sources familiar with the investigation.

The sample, originally processed by a private Florida lab, was recently transferred to the FBI for advanced testing using newer technology.

Officials say the DNA appears mixed from multiple individuals, making it difficult to separate and analyze.

Investigators from the FBI and Pima County Sheriff’s Office are still actively working the case, with several labs assisting in the effort, ABC News has reported.

Despite early leads and released evidence, authorities say the investigation has made limited progress and the victim’s family continues to seek answers.