Was Sal Mineo's Killer Ever Caught?

The late Sal Mineo was found dead, under suspicious circumstances. Did the police ever identify a sustpect?
As I remember, Mineo’s career was in decline, and he wasn’t living in the best of neighborhoods.

Apparently so.

Well, not sure what the neighborhood was like back then, but currently it is in the heart of West Hollywood, and it ain’t cheap to live anywhere near there. The building where he lived and died is just a couple blocks from Barney’s Beanery*, a local hangout for Bogart and Bacall and lots of other celebrities back then - as well as Jimi Hendrix and also being the last place where Janis Joplin was seen in public before she died. Estelle Getty lived just around the corner from Mineo’s apartment building until she died, and quite a few celebrities live, or have lived, within easy walking distance of that location.
*Barney’s Beanery was also a sore point for Gay activists - for years they had a sign that said, “No Fags” that was supposedly “a joke” about smoking, but most knew what it really meant and what the owner’s policy was. It was a big deal when they were finally forced to remove the sign from the entrance - but that is another story.