DNA testing of hair from the home of Nancy Guthrie has not led investigators closer to a suspect in her disappearance, Pima County Sheriff Chris Nanos said Thursday. Pima County Sheriff Chris Nanos said multiple labs are working on another mixed DNA sample from Guthrie's home. Meanwhile, a mixed DNA sample retrieved from Guthrie’s Tucson-area home contains up to four people, Nanos told ABC. “We have some of the brightest minds in the nation, if not the world, working on this.” Amid criticism of the sheriff’s handling of the stalled investigation, Nanos told People in May that the department is getting closer to answers.