See Orlando terrorist pictured Omar Mir with his wife and son

In the picture the 29 year old Omar Mateen is seen smiling with his kid and wife. The. The loving father now transformed to be a terrorist who carried out America's deadliest mass shooting, leaving old friends and family members in shock.

Mateen walked into a gay nightclub in Orlando, Florida, with a handgun and AR-15 semi-automatic rifle, killing 50 people on Sunday before police stormed the club and fatally shot him.

A gay, high school classmate who knew Mateen before 2009 said the 29-year-old regularly interacted with him and his other gay co-workers and 'treated us all like the individuals we were.'

But the terrorist's father said his son had recently become infuriated at the sight of two men kissing, while others said he was an 'agitated' and 'aggressive' bodybuilder.

Mateen's first wife claimed he was mentally ill and physically abusive, while a coworker said: 'He talked about killing people all the time. I wasn't shocked. I saw it coming.'

The terrorist's father Seddique Mir Mateen also denied that the attack had anything to do with religion, and said his son had become enraged after seeing two men kissing in Miami months before.

While the father said he was 'in shock like the whole country,' the terrorist's former coworker, Daniel Gilroy, told the Times: 'He talked about killing people all the time.'

Gilroy said he made several complaints to G4S, the company where they both worked, because Mateen frequently used racial, ethnic and sexual slurs and sent him a barrage of 20 to 30 text message a day.

'He was always shaken, always agitated and always mad,' Gilroy added. 

Sitora Yusufiy, Omar Mateen's first wife, described how he 'seemed like a normal human being' at first. The two met online and married in 2009 after a brief romance

Following a brief romance after the two met online, the pair married in 2009 and moved into a two-bedroom home owned by Mateen’s family in Fort Pierce.

‘After a few months he started to beat me,’ she said. ‘He was mentally unstable… he was obviously disturbed. I know he had a history of [taking] steroids. 

'He was not a stable person. He would just come home and start beating me up because the laundry wasn’t finished or something like that.' 

Yusufiy said that Mateen owned a gun during their marriage, was ‘short tempered’ and would express ‘hate towards things’. She would not reveal if he had any homophobic views.

Her parents eventually intervened and the two separated, although their divorce wasn't finalized until 2011.

See Orlando terrorist pictured Omar Mir with his wife and son