Former teachers and classmates paint disturbing picture of Orlando shooter Omar Mateen

Omar Mateen, who authorities say killed dozens of people inside the Pulse nightclub in Orlando, Florida. Photo / AP

A disturbing picture is emerging of Orlando nightclub shooter's troubled childhood, as former teachers and classmates share confronting memories of him from his primary school days.

Their stories reveal Omar Mateen, then known as Omar Seddique, was having homicidal and misogynistic fantasies as early as age 10.

Leslie Hall, who was Mateen's classmate at Mariposa Elementary School in Florida and target of his bullying, remembers him getting suspended in the fifth grade for threatening to shoot up the school.

Other classmates and a former teacher have similarly unpleasant recollections of Mateen, describing a boy who was driven to school in a limo, often taunted less affluent kids and even stole toys.

They remember how "all the girls were scared of him", even his mother and sister.

According to staff members, numerous attempts by the school to intervene failed because of the "enabling" nature of Mateen's father, Seddique Mateen, who was considered to be the source of his attitude towards women and girls.

Omar Mateen's ex-wife Sitora Yusufiy has told of being beaten on an almost daily basis during their four months together, describing him as "unhinged", "bipolar" and "psychopathic".

Sitora Yusufiy, ex-wife of Orlando shooter Omar Mateen, talks about her ex-husband. Photo / AP

Ms Hall's father Bill said Mateen's bullying got so bad that he made a formal complaint to the school.

"There were issues with that kid, oh lord. He treated all the girls bad," Mr Hall, 62, told the New York Daily News.

"She would come home and she was upset, visibly upset. She was really bothered by him.

"The school was well aware of his issues. They should've taken more action. I mean, there were flags all over the place about this guy.

"We weren't the only ones. Other students' parents and other students also made complaints about him."

Katherine Zurich, 62, who taught Mateen in the fourth and fifth grade, said she tried to reach out to him but found his attitudes too deeply entrenched to penetrate.

"He felt that women were beneath him," Ms Zurich said.

"He was taught to disrespect them. His mum, his sisters were afraid of him. They had to be subservient to him because he was the son. They treated him like the father, with respect."

Ms Zurich said Mateen would boast about how rich his family was, yet delight in taking things from other children.

"He felt his family was wealthy and that he was superior and had to be catered to," she told The News.

"He would say to other kids, 'You're poor, you don't have anything.' He was mean-spirited. On the playground he would take things first. He would grab someone's ball from them, things like that.

"He struggled with reading and with other subjects. I think this was his way of deflecting his own insecurities."

Omar Mateen. Photo / AP

Ms Zurich said many teachers, including herself, raised their concerns about Mateen's behaviour directly with his family but were always fobbed off.

"The father, he was a pig. He always felt like he was the victim," she said. "He was never mean to me because he knew I had his son's best interest in mind. But he was disrespectful to women at large. He just felt women were not to be valued," she said.

"He was in denial about his son even then. He would say, 'Oh Omar, he does nothing wrong'."

The former teacher's words echoed comments made by Seddique Mateen in the wake of his son's attack on the Pulse nightclub, which left 50 dead, including Mateen, and 53 others injured.

Mr Mateen snr blamed the massacre - the worst mass shooting in US history - on the club's poor security rather than the actions of his son, whom he has described as "a good boy".

One teacher warned Mr Mateen that Omar was "going to get himself shot" if he didn't stop picking on other kids, but the father simply turned a blind eye.

That teacher, who declined to be identified in an interview by CBS affiliate WPEC, said every staff member at Mariposa Elementary was concerned about Mateen and where his behaviour would take him.

"I can honestly say of all my students there were two that I knew they were going to grow up to hurt someone," the teacher told WPEC.

"The ground work was done with the family. We did not get support from his father."

The teacher alleged Omar claimed his father often told him he did not have to listen to women, which was a problem at Mariposa, where most of the faculty at the time was female.

"He seemed to be so disturbed and violent, it was hard to make him change," the teacher said. "Hard to look back and say what we thought would come true did."

Ms Hall, who was bullied by Mateen, said he would also take out his aggression on teachers, throwing chairs in class and worse.

"He was very disrespectful," she said. "He was spitting in teachers' faces."

Multiple classmates remember the day he threatened to carry out a massacre, earning him a two week suspension in fifth grade.

"He was going to bring a gun to school and threatened to kill everyone he didn't like," Ms Hall said.

"He made that comment in passing to me and my friends. We were in the hallway and he made that comment."

Christopher Diaz also remembered the threat from the boy he described as a "troublemaker and a "loner".

"He said he was going to bring a gun to school," Mr Diaz, 28 told TMZ. "Everybody knew he said it."

Their stories come just one day after Mateen's former classmates at Martin County High School recalled seeing him celebrate the September 11 terror attacks in New York.

Ex-student Robert Zirkle said Mateen "was making plane noises on the bus (on the way home), acting like he was running into a building."

"After 9/11 happened, he started changing and acting different," he said.