Darwin Vela vanished Tuesday, two days before he was supposed to testify in a preliminary hearing for Ricardo Orozco -- who is accused of attempting to extort Sheen over a sex tape -- TMZ reported.
Police said Vela was discovered Friday in South Los Angeles. He flagged down a passerby and had them call 911.
He told police he was kidnapped.
Vela and Orozco are accused of going to Sheen's representatives, saying they had a sex tape featuring the actor and asking how much it was worth, TMZ reported.
Orozco was arrested and charged with burglary for allegedly stealing computers, including one that contained the sex video.
There was no word on whether Vela was charged in the alleged extortion.
A law enforcement source told TMZ Vela was injured, but the specific injuries weren't reported.