The man leading the investigation into the high-profile disappearance of 84-year-old Nancy Guthrie, the mother of NBC "Today" host Savannah Guthrie, is a longtime law enforcement officer with a half-century of experience under his belt.

According to his partisan election by a razor-thin margin, defeating his Republican opponent Mark Napier by only 0.7%.

Four years later, he battled to keep his elected position in an even tighter race, winning 49.9% of the votes against Republican challenger Heather Lappin, who earned 49.8%. His margin of victory was 481 votes, and he was declared the winner several weeks after the election following a contentious recount.

In fact, Nanos' last election was marred by controversy.

In the weeks leading up his 2024 election, Nanos reportedly placed his opponent Lappin, a lieutenant at the Pima County Jail, on administrative leave, ordering her not to discuss the reasoning for his decision. He did the same to Sgt. Aaron Cross, an outspoken opponent of Nanos and the head of the Pima County Deputies Organization.

Cross reportedly campaigned against Nanos, holding a sign on a street corner saying "Deputies Don't Want Nanos," just before he was placed on leave. Nanos claimed Cross campaigned against him while wearing his Pima County sheriff's uniform in breach of department rules, which Cross denied. Cross later filed a federal lawsuit against Nanos, claiming the sheriff violated his First Amendment rights.

Nanos also reportedly faced a criminal election interference investigation stemming from the matter.

The sheriff has also faced heat for his handling of an internal investigation into a 2022 sexual assault of a female deputy by a supervisor in 2022.

In his current role, Nanos oversees 1,500 employees and 400 volunteers, serving more than one million residents in a county that covers about 9,000 square miles.

Nanos and the sheriff's department did not return requests for comment.

The search for Guthrie is entering its fifth day. So far, little information has been released about the nature of the investigation, and a suspect has not been named. 

Law enforcement on Tuesday acknowledged that it was aware of potential ransom notes sent to several media outlets.