A San Francisco, California, assistant teacher is accused of calling bomb threats into the preschool he worked at.

Pablo Munoz, 22, supposedly left the calls on the LePort Montessori School’s voicemail on May 8 and May 16. According to the KGO-TV, the school was evacuated and police recovered no explosive devices during both instances.

The San Francisco Chronicle pointed out that the preschool serves children ages 3 months old through kindergarten.

The 22-year-old was arrested at his job on Friday. Police said he was booked into the San Francisco County Jail and is facing two felony counts of making threats and two misdemeanor counts of falsely reporting a bomb to the school, according to the East Bay Times.

“We are thankful for how quickly and thoughtfully law enforcement acted to protect our community,” Greg Marick, LePort Schools’ vice president of operations, said in a statement on Tuesday. “The well-being, health, and safety of our students remains our first priority and we are committed to doing all we can to support them through this time.”

The investigation was carried out by the San Francisco Police Department’s Special Investigations Division, according to the San Francisco Examiner. Authorities claimed they identified Munoz as a suspect early on in their investigation.

Despite his arrest, school officials told KNTV it’s unclear why Munoz placed the bomb threats. The station claimed the 22-year-old had no criminal history and gave no indication that he was disgruntled.

A spokesperson for the San Francisco Sheriff’s Department revealed to the SFist that the assistant teacher has since been released on bail.

KNTV reported that Munoz is on administrative leave pending a school and police investigation.

[Featured Image: San Francisco Police Department]