Ezequiel Padilla-Villalobos, who is accused of stabbing his girlfriend’s 14-year-old sister to death, will also be charged with sexual assault.

He will be charged with murder in the first degree, felony murder and five counts of sexual assault, Adams County District Attorney Don Quick announced Friday.

Padilla-Villalobos, 24, called 911 late Sunday to report that he had killed a woman. He later told Commerce City officers that he was drinking heavily and using cocaine before his girlfriend, FlorMaria Acosta, sent him a text message asking him to get her sister Gaby from their mother’s house in Broomfield.

Padilla-Villalobos told police things went wrong when he began having what he described as “thoughts of killing while he was driving,” according to a police affidavit.

Detectives discovered Gaby’s body in the 8600 block of Verbena Street near a stable where Padilla-Villalobos told police he had helped his friend shovel horse manure earlier in the day.

Padilla-Villalobos said he leaned over and started strangling the girl as soon as he parked the truck on Verbena Street. She struggled against him before he stabbed her with a kitchen knife that he had used to cut vegetables days before, the affidavit says.

Police found Padilla-Villalobos covered in blood at a Diamond Shamrock gas station, where he called 911 just before midnight Sunday to turn himself in. He told police “he felt so bad for the bad thing he had done.”

The murder charges are Class 1 felonies, and the sexual-assault charges range from Class 2 to Class 3 felonies, Quick said.

FlorMaria Acosta has two young children with Padilla-Villalobos.

Padilla-Villalobos’ preliminary hearing and bail hearing are scheduled for March 8 at 9 a.m.

Megan Mitchell: 303-954-1223, mmitchell@denverpost.com or twitter.com/megs_report