Tinsley was last seen at Lake Overholser in Oklahoma City, Oklahoma on April 13, 1986. She was there with friends when, at 2:00 p.m., she said she was going to take a ride around the lake on a motorcycle with a man she had just met. Tinsley left her purse and cigarettes behind with her friends. She never returned from the ride and has never been heard from again. Tinsley's companion is described as Caucasian, 6'0 and 180 to 200 pounds, with brown hair and possibly a brown moustache. He was between 19 and 23 years old in 1986. He wore jeans, a t-shirt and sunglasses. His motorcycle was a blue 650 cc or 750 cc Kawasaki model. He has never been identified.

Tinsley was having personal problems at the time of her disappearance. Three other people lived with her at her one-bedroom apartment in the 1200 block of north Kennedy in Edmond, Oklahoma. All of them were unemployed and none of them paid rent, and Tinsley had decided to evict them. A couple of weeks before her disappearance, the police discovered marijuana growing in her closet. Tinsley said the marijuana wasn't hers. Her fiance was serving with the military in another state, and he wrote to her regularly asking her to send him drugs.

Tinsley's mother stated it would be very unusual for daughter to accept a ride with a stranger, or to leave her purse and cigarettes behind. She believes the motorcycle rider Tinsley met on the day of her disappearance was someone known to her, and that her disappearance may be drug-related. There is no indication that Tinsley left of her own accord; she left behind all her belongs, including her clothes and her Volkwagen, and she was engaged to be married and would be unlikely to run away with another man. Tinsley worked as a newspaper deliverer for the Oklahoman at the time she vanished. Her parents are still alive and still hope she will be found. Foul play is suspected in her case, which remains unsolved.