Harkins was last seen at Suney's Pub on Chandler Street in Worcester, Massachusetts on February 15, 1994. He has been been heard from again. He left his wallet, cigarettes, hat, coat and money when he disappeared.

Authorities believe Harkins got into a black 1985 Chevrolet Impala with Matteo Trotto after he left the bar. That same vehicle was pulled over for speeding on Route 146 very early the next morning. Elias Samia was driving, John R. Fredette was in the passenger seat, and blood was on the roof and the passenger side door. Police let the car go without searching it. It has never been located. Samia later said he'd junked it, but in 2005 the fire department found a car roof, a front passenger side car door, and other parts believed to be from the Impala.

Although there is no hard evidence to indicate foul play, police believe Harkins was murdered. He was supposed to testify on the behalf of one of his associates two days prior to his disappearance; the man was on trial for drug charges and pleaded guilty after Harkins did not show up to testify. He did not begin serving his sentence until two days after Harkins disappeared. On the night Harkins vanished, this man was known to be bloodstained, and claimed he had gotten into a bar fight.

Matteo Trotto, is presently serving 23 to 30 years in prison for cocaine trafficking. Elias Samia, now lives in Rochdale, Massachusetts, and Fredette, lives in Maine. All deny involvement in Harkins's case, but they have been named as suspects in his disappearance. His case was brought before a grand jury in 2006, and he was declared legally dead in 2008. His disappearance remains unsolved.