A Colorado man is behind bars after a surveillance operation caught him inappropriately touching teenage girls at a Starbucks near their high school.

Sergio Gallegos-Munoz, 40 of Denver, was booked into the Arapahoe County Sheriff’s Office Detention Facility on Monday on three counts of sexual assault on a child and three counts of unlawful sexual contact, according to KDVR.

The sheriff’s office said it had received several reports over a one-month period of a man having unlawful sexual contact with the teenagers. The teens reported they were approached from behind by a man who then grabbed their buttocks.

At about 6 a.m. Monday, investigators were conducting surveillance at the Starbucks when a man matching Gallegos-Munoz’s description entered.

A Starbucks employee told investigators that the man was the one they recalled seeing at the time of the the previous reports.

A previous victim who happened to be inside the coffee shop at the same time identified Gallegos-Munoz as the suspect in her case.

Deputies then took Gallegos-Munoz into custody.