Don Cornelius Suicide -- LAPD Capt. on Scene Was Once on Soul Train!

The LAPD captain who ran the crime scene on the day Don Cornelius killed himself was no stranger to the legendary TV host ... because in her younger days, she appeared on "Soul Train" ... TMZ has learned.

Captain Tia Monett Morris joined the Los Angeles Police Department back in 1981. But before she was solving crimes, Capt. Morris appeared on "Soul Train" as a dancer back when she was a teenager.

We called Capt. Morris for details about her time on the show -- but she was tightlipped, only confirming she had indeed appeared on the show.