Rihanna's alleged stalker is reportedly being electronically tracked by police.

An LAPD source has told TMZ that a man going by the names Alex Mercer and Ralph Alexander on Twitter and Yahoo is being investigated.

It comes after the guy in question posted a selfie of himself standing outside Rihanna's former home on April 30. The following day he tweeted, "Should of killed @rihanna a minute back I would be good right now. Sorcery is a weapon I use guns, bout to get a gun license, can’t use my hands (sic)," reports the news outlet.

Police flocked to the house but he was gone by the time they got there. Now the cops are trying to track him down electronically, through phone, computer and social media.

This isn't the first time the 27-year-old has been harassed by a stalker. In 2013 she was hounded by Kevin McGlynn. He was arrested after hand-delivering letters to Rihanna's New York apartment, where he called her a b***h and threatened to gang rape her.

Talking about the case in 2014 Judge Orlando Marrazzo compared Kevin to John Lennon's killer Mark David Chapman.

Kevin also claimed he was in a relationship with Rihanna and that she stole his music.

"[Kevin] appears to be a ticking time bomb who is wholly fixated on (Rihanna), and poses a direct threat of serious physical harm or death to her and anyone around her," judge Marrazzo said in November 2014.

"It is entirely foreseeable that if he were free to continue to act upon his psychotic delusions without this court's intervention, it may result in the death of (Rihanna) or other innocent persons."

In September 2014 Kevin was found unfit to stand trial and was committed to a psychiatric hospital.