WAUKEGAN, Ill. (CBS) – A Round Lake Beach man could go to prison for the rest of his life if a jury finds him guilty of sexually abusing three girls who were all under the age of 13.

Bernabe Molina III, 35, pleaded not guilty earlier this week before Lake County Judge Fred Foreman. He is charged with three counts of predatory criminal sexual assault and one count of criminal sexual assault, and appeared for his arraignment on Tuesday.

Molina formally denied charges involving a third alleged victim Tuesday, according to Assistant State’s Attorney Reginald Mathews.

Authorities learned about the third girl, who was under the age of 13 at the time of the alleged abuse, while they were investigating allegations regarding two other girls under the age of 13, Mathews said.

The sexual abuse started when each of the girls was about 5 years old and continued for about five years, he added.

Molina has previously pleaded not guilty to predatory criminal sexual assault charges regarding the first two alleged victims, Mathews said.

If convicted, Molina could spend up to 30 years in prison for the predatory charge and four to 15 years for the criminal sexual assault charge.

However, he faces up to natural life in prison if convicted of committing sex acts with the three girls, Mathews said, pointing out that under Illinois law a person charged with predatory criminal sexual assault for two separate victims faces life in prison.

Molina remains in custody at Lake County Jail in lieu of $1 million bond. His trial is scheduled for Aug. 8, and he is due back in court July 12.

The Lake County News-Sun contributed to this report, via the Sun-Times Media Wire