A registered sex offender in California has been arrested on suspicion of raping a 19-year-old gay homeless man.

According to Mercury News, Chad William Swanson, 44, of San Jose, had become friends with the man, and had persuaded him to live at his home.

In exchange for the favour, he agreed to help Swanson with his vending business at local flea markets in the area.

But then on 22 October, Swanson reportedly abused the individual as he slept.

The San Jose Police Department said Swanson already has a conviction for lewd acts with a child younger than the age of 14.

Detectives said the suspect had previously been seen hanging around the Billy DeFrank LGBT Community Centre and a nearby coffee house in San Jose.

They are appealing for anyone who may have been a victim of Swanson to contact them via the SJPD sexual assault unit.