Investigation Into Nancy Guthrie Disappearance Reaches 100 Days

The investigation into the disappearance of Nancy Guthrie reached its 100th day on Monday with investigators still awaiting results from DNA analysis at an FBI laboratory. Guthrie was reported missing Feb. 1 from her home in Tucson, Arizona. DNA recovered from the residence was first sent to a private laboratory in Florida before being forwarded to the FBI laboratory in Quantico, Virginia, where the work remains ongoing, law enforcement sources told CBS News.

Officials have not publicly detailed the nature of the DNA sample or its precise location in the home. A former FBI supervisory special agent in Arizona said that a strand of hair found near a victim's last known location, such as in a bed, would receive high priority at the FBI laboratory.

The analysis process, which can include building family trees and conducting forensic comparisons, requires extensive time to ensure accuracy. The sheriff stated it would be inappropriate to discuss evidence in order to preserve the integrity of the case and ensure any suspect receives a fair trial.

If the sample is bodily fluid, it would allow for a more complete DNA profile than skin cells, which often produce lower quantities. A full hair follicle containing a root would be more useful than a strand without one. Sources close to the investigation said laboratory techniques can enhance even low-level samples, though the process may take additional time.

Earlier in the inquiry, DNA recovered from gloves found about 2 miles from the home was traced to a restaurant worker with no connection to the case. A spokesperson for the Pima County Sheriff's Department said in a statement that scientific evidence processing and digital media analysis remain ongoing at the 100-day mark.