The man who authorities believe opened fire inside a Texas elementary school, killing 19 students and two teachers on Tuesday, displayed violent tendencies and had a troubled home and school life, according to reports.

Friends, family, neighbors, and co-workers of 18-year-old Salvador Ramos, the suspected gunman, told media outlets in the aftermath of the shooting at Robb Elementary School in Uvalde, Texas, that Ramos was generally quiet but at times could be threatening, violent, and displayed unstable behavior.

TEXAS SCHOOL SHOOTING DEATH TOLL RISES TO 19 CHILDREN AND TWO TEACHERS

A neighbor recalled arguments between Ramos and his mother that were serious enough to lead to police coming to the house Ramos lived in with his mother until recently, according to a report. In at least one of these cases, the suspected shooter reportedly posted a video on Instagram of him "screaming" at his mother while police were present.

The report noted that multiple people close to Ramos's family said his mother was a drug user.

The suspected shooter reportedly also had trouble in school, dropping out of Uvalde High School.

A high school classmate of Ramos recalled him being involved in at least five fistfights with classmates, according to a report.

“He wasn’t very much of a social person," a cousin of the suspected school shooter told a media outlet, claiming Ramos was bullied in school for stuttering. Other friends and family members also claimed that Ramos was mocked in school for having a lisp, as well as for wearing eyeliner, according to a report.

Reports have also emerged about other disturbing behavior from Ramos prior to the shooting.

A friend of Ramos told a media outlet that he once showed up at a park basketball court with cuts all over his face, claiming that he had used knives to cut up his own face for fun. The friend also claimed Ramos would drive around at night with another person to shoot people with a BB gun and throw eggs at cars.

A woman who worked alongside Ramos at a Wendy's restaurant claimed he could be "very rude" and "threatening" toward women and one of the cooks at the restaurant, according to a report.

“He would be very rude towards the girls sometimes and one of the cooks, threatening them by asking, 'Do you know who I am?' And he would also send inappropriate texts to the ladies,” Ramos's former co-worker said in the report.

The woman also said she had seen videos of Ramos "trying to fight people with boxing gloves," which he would carry around with him.

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Ramos was shot and killed by a Border Patrol agent who arrived at the scene of the massacre. The agent was wounded in the gun battle.

Police believe Ramos shot his grandmother before the mass shooting at the elementary school.

Authorities have not released a motive for the shooting.