Rihanna Alleged Stalker Sends Alarming Masturbation Video

1/31/2016 12:40 AM PST

0129-rihanna-tmzRihanna has an alleged stalker who was so invasive in her life, he sent her a masturbation video.

According to a search warrant, obtained by TMZ, the man had been dogging Rihanna, sending her threatening tweets between April and June of last year, saying among other things, "Should have killed @rihanna a minute back I would be good right now."

The man also said, "I use guns, bout to get a gun license."

But the search warrant makes it clear the man did things even more deranged, posting a 15 second masturbation video to Rihanna.

As we reported, the man also posted a pic (below) of him standing outside Rihanna's former home, saying, "Outside yo house."

0707-sub-rihanna-ralph-alexander-stalker-instagram-4The warrant says Rihanna's in fear for her life.

We're told cops found the guy and put him in a psychiatric hospital, where he remains.