Tyler Brehm, the Hollywood gunman, launched the deadly rampage because he was dumped by his girlfriend

Tyler Brehm, the Hollywood gunman shot dead by police as he fired randomly at passing cars on a street had been struggling to overcome the recent break up of a four year relationship, according to friends.

Passers-by initially thought the gunman was an actor from a movie being filmed nearby – until he was shot dead by a policeman.

Tyler Brehm, 26, wounded three people – one critically – before he was killed by an off-duty officer working as a security guard on the neighbouring film, believed to be a gangster thriller starring Sean Penn.

When television crews told neighbours and friends the identity of the shooter, they said Tyler Brehm had been struggling to overcome a breakup with girlfriend Alicia Alligood.

“He wasn’t a bad guy, he just got fed up,” friend Christina Mesropian told KNBC.

“He was like <<Ah, I’m over it, I’m over it>>, but I could tell he wasn’t over it.”

Alicia Alligood, 24, told a reporter she and Tyler Brehm had “been dating for four and a half years” before breaking up on December 1. He then moved to his own apartment half a mile from the scene of the shooting.

Tyler Brehm had texted his former girlfriend minutes before the shooting rampage, and hours earlier had left her a voicemail saying he loved her, she told KTLA.

They went to school together in Pennsylvania and began “hanging out” during their college years.

Alicia Alligood described her former boyfriend as a “humanitarian”, and someone who was “extremely motivated to change the world for the better”, even managing a non-profit organization for a friend.

But, the woman also said Tyler Brehm was “really stressed out lately”.

Tyler Brehm had met a woman he thought was a pharmaceutical saleswoman who had given him some kind of pills, Alicia Alligood said. He began taking the pills, which his ex-girlfriend found alarming as he never took “hard” drugs before.

Ramon Hernandez, who lived in the apartment next door to Tyler Brehm, said the couple had recently moved out. He told KABC-TV he had heard them arguing.

“I could tell that he was an unstable person,” Ramon Hernandez said, “but I don’t know the details on what actually made him snap.”

Tyler Brehm walked down the middle of Sunset Boulevard, firing on motorists and in the air until he was shot and killed.

He was filmed from an office block standing in the middle of the road firing on pedestrians and motorists.

In the video, he can be seen pacing back and forth near the busy intersection with Vine Street, firing close to 20 rounds from what appeared to be a .40 caliber handgun.

One of his victims has been name as John Atterberry, 40, a former music industry executive who has worked with artists like Brandy, The Spice Girls and Jessica Simpson.

The man, who was driving a Mercedes-Benz, was shot in the jaw and upper torso and taken to hospital, where he remains in critical condition.