A man who was charged with possessing child pornography after his girlfriend alerted police to images she found on his cellphone is now facing accusations that he sexually assaulted two minors.

Christopher Negrete, 42, appeared in court March 1 for a possession of child pornography charge after his girlfriend found the alleged images and reported them to Chicago police.

At the time, Cook County prosecutors said at least five images were found on his phone that depicted children — some younger than 5 years old.

On Friday, prosecutors said they now have charged Negrete with two counts of criminal sexual assault and an additional count of child pornography.

The new charges stem from accusations made by a woman who read about Negrete’s previous child porn charge and came forward, as well as accusations made by the daughter of the girlfriend who turned him in the first case, according to court documents.

The woman who came forward after reading coverage of Negrete’s initial case said Negrete had her pose topless when she was 14, so he could take “artsy pictures” of her, prosecutors said. When she was 16, Negrete began having sex with the then teenager and took additional pictures of her while they had sex.

Prosecutors said those incidents took place between 2005 and 2008.

Negrete was also accused Friday of sexually assaulting the 5-year-old daughter of the woman he was in a relationship with when he was charged in March. Prosecutors said the woman took her daughter to a therapist to help explain and discuss why Negrete was moving out of their home.

During the session, the girl said Negrete had touched her when she was naked and that Negrete had told her not to tell her mother, prosecutors said. Negrete also allegedly took photos and videos of the girl as he approached her to touch her. Prosecutors said the girl told authorities about the attack during a videotaped interview.

Prosecutors said Negrete’s phone and computers are being examined and that additional charges could be filed against him if more evidence is discovered.

Negrete was initially ordered held on $10,000 bail, but it was increased to $250,000 after he tried to contact a witness in the case by writing the witness a letter while being held at the Cook County Jail.

On Friday, Judge Stephanie Miller ordered Negrete held without bail on the latest charges.

Negrete had been living Jefferson Park at the time of his arrest, according to police records.

Assistant public defenders who have represented Negrete said he grew up in Kansas before attending Northeastern University. He had been working for a trivia company at a bar when he was arrested and has lived in Chicago for more than two decades, his attorneys said.