Lt. Keith Czeskleba said Sign's death is being investigated as an apparent suicide.
Eric Land, VP and general manager of ABC 33/40, said:
Our deepest sympathy is shared with Christopher's loving family and close friends. We have lost a revered colleague who's indelible imprint will serve forever as a hallmark of decency, honesty and journalist integrity. We can only hope to carry on his legacy. May his memory be for blessing.
Sign was 45 years old. He is survived by his wife and three children.
What about the Clinton-Lynch story?
Sign gained national attention in June 2016 when he broke news that Bill Clinton privately met with Lynch on the tarmac of Phoenix Sky Harbor International Airport.
At the time, Sign worked for KNXV-TV in Phoenix.
The Clinton-Lynch meeting triggered immediate controversy because it came as the FBI was investigating Hillary Clinton for her use of a private email server during her tenure as secretary of state. The meeting, in fact, came just days before then-FBI Director James Comey announced Hillary Clinton would not face criminal charges for using her private email server despite possibly mishandling classified information.
Both Clinton and Lynch denied discussing the FBI's investigation, instead claiming their conversation, which lasted between 20-30 minutes, was personal in nature.
Department of Justice Inspector General Michael Horowitz's report on the FBI's Hillary Clinton email investigation indicated that Lynch's staff that felt "blindsided" and "shocked" that she would meet with Clinton. The IG report said a senior Lynch staffer ended the meeting when she realized its problematic nature.
Sign later wrote a book about the meeting — "Secret on the Tarmac" — and told Fox News last year, "there's so much that doesn't add up" about the meeting.