This image shows the booking and release center at the Orange County Jail in Orlando, Florida, July 15, 2011. Joe Raedle/Getty Images

A Florida woman, who was arrested and charged with the death of her 11-year-old daughter Monday, allegedly stabbed the girl over a dozen times because she thought the girl was having sex with someone.

Rosa Alcides Rivera, 28, drove her daughter, Aleyda Rivera, to Winnie Palmer Hospital for Women and Babies in Orlando, Florida, on Sunday and sought medical assistance for her. Staff at the hospital checked on the girl who was lying in the back seat of her mother’s car and determined that she was dead. On being informed of her daughter’s death, Rivera became aggressive and produced a blood-soaked knife, forcing the hospital staff to put the facility under lockdown and close the main entrance for a brief period of time.

Investigators from Orange County Sheriff’s Office arrested Rivera who admitted to killing her daughter. Police body camera footage shows her saying, “my baby is gone." She was charged with first-degree murder.

According to her arrest documents, Rivera said she killed her daughter to “prevent her from having sex” with men. The 11-year-old was stabbed as many as 15 times on and around her back. She also had a defense wound on her right arm. Rivera had a self-inflicted cut on her right arm. When asked if she had any other injuries, she confessed to fatally stabbing her daughter.

She was taken to Orlando Regional Medical Center for treating her injuries, after which she was sent to the Orange County Jail. She was held without bail.

According to investigators, witnesses saw Rivera pounding on the door of a home in one of the blocks of Citadel Drive on Sunday morning. She accused a man living there — who was her mother’s boyfriend — of having sex with her daughter. Though the girl denied having sex with anyone, her mother refused to believe it. Police believe the girl was stabbed in the car after which Rivera drove the child around in the car till she died from her wounds.

“Rivera stated she stabbed her daughter while in the car, and while stabbing her she was attempting to make her more comfortable,” according to the arrest report by an investigator.

On being questioned if she ever saw her daughter having sex, Rivera said she didn't and neither did her daughter told her she had sex with anyone. She said she believed her daughter was having sex because she began to smile “different.” Rivera told the deputies she believed Aleyda was in heaven.

“These cases are horrific and tragic. And then to know that the child was killed by a mother — basically, a mother is the first line of defense to what is sometimes a very cruel world— is very hard on all of us,” Orange County Sheriff John Mina said in a press conference.

Detectives were investigating if the girl was sexually abused. “Based on what we know and what we’ve found so far, we believe that part to be false. We are doing everything we normally do in those types of allegations, investigations, to unfound that completely,” Mina told reporters.