A schoolgirl in Italy was gang-raped and killed by four men before being dumped in a derelict building, a court has heard.

Desirée Mariottini, 16, was found dead in a building site in the area of San Lorenzo, Rome, on October 19, 2018.

The trial for the teen, who would have turned 18 on the September 14th, resumed at the Criminal Court of Rome last Thursday.

In the hearing, judges heard the testimony of a witness who saw the girl the day before her death.

Narcisa Leon, an Ecuadorian woman who was squatting in the derelict building around the time of the incident, told the court she found the teen lying motionless on a mattress.

According to Corriere della Sera, the witness said: "One of the defendants confessed to me that he’d had consensual sex with Desirée after giving her drugs. He admitted it.

Desirée Mariotinni
The jury heard the girl was drugged and raped before her body was dumped

"Two other defendants also admitted to having sex with her."

Four men — Yusuf Salia, Mamadou Gara, Brian Minteh, and Chima Alinno — are on trial for the rape and death of the 16-year-old.

They are accused of drugging the teen, before raping her in turns, then leaving her to die.

The defendants face criminal charges for voluntary murder, group sexual violence and drug dealing.

Mamadou Gara
Mamadou Gara, middle, is one of the four men standing trial accused of killing the teenager

Leon claims the teen went to the abandoned site to buy drugs from the four men.

After finding the body, she claims one of the defendants, Mamadou Gara, said: "better her dead than us in jail."

Other people who were at the site, did nothing to help the teenager after hearing what the suspected drug dealer said.

Desiree Mariottini
An autopsy confirmed the teen died as a result of delayed medical intervention

Leon also said that the suspects handed the victim a cocktail of drugs before having "sex with her".

An autopsy confirmed that Mariottini died of cardiorespiratory arrest, as a result of delayed medical intervention.

It concluded the 16-year-old would have likely survived had the emergency services been called after she was found unconscious.

The case is ongoing.