Omar Mateen carried out an attack on Orlando nightclub Pulse which left 49 people dead on Sunday morning (June 12).
Now, Mateen's ex-wife Sitora Yusufiy has stepped forward and revealed that she recognised something "deeply" wrong with him years ago.
Speaking to ABC News
, Yusufiy said: "He would be perfectly normal and happy, joking, laughing one minute - the next minute his temper... his body would just [go] totally the opposite."
She continues, revealing how Mateen had abused her.
"Anger, emotionally violent and that later evolved into abuse, to beating," she adds.
"After being abused and after trying to do that and see the good in him, I can honestly say this is a sick person. This was a sick person that was really confused and went crazy."
Yusufiy explains that Mateen was religious, but not radical as he was "Americanized".
The pair had met online in 2008 and dated for a short period of time before getting married, ABC News reports.
Yusufiy also says that just weeks into their marriage, Mateen had made her get a job and would take the money she earned.
"It was just his personal form on control. He wanted to control me and do whatever he [could] to keep me hostage," she said.
"In those moments of emotional instability, he would express his anger towards [a] certain culture, homosexuality, because in Islamic culture, it is not really tolerated, homosexuality. And I know at the time he was trying to get his life straight and follow his faith."
The relationship came to an end when Yusufiy's and Mateen's family had a disagreement and Yusufiy was "rescued" by her parents before officially divorcing in 2011.
She clarifies that she had no contact with Mateen since leaving him however he attempted to contact her through Facebook but she blocked him. Yusufiy had previously thought that everything was behind her.
She said, "I thought I had closed the chapter on this horrible mistake that I had gotten myself into and forgot all about it and we're free from it. But this is the most shocking, heartbreaking experience."
ABC News states that Yusufiy offers her sympathies to the grieving families.
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