Three teenagers are under arrest for allegedly making online threats to two high schools in Rocklin.  

Rocklin police began investigating a vague online threat posted on an Instagram forum back on April 10. It mentioned Whitney High School and included the Instagram profiles of 24 students. 

Police investigated the possible threat a month ago but did not find it to be credible. However, Captain Lon Milka with the Rocklin Police says during the investigation other social media threats to Whitney and Rocklin High Schools were uncovered.

"We had three arrests, two with juveniles, one with an adult, and they were associated with secondary threats that we discovered on social media yesterday," Milka said. 

The two unidentified, underage teens were placed into the Placer County Juvenile Hall and 18-year-old Justin Hermann was booked into the Placer County Jail for allegedly making criminal threats. 

The online threats had parents concerned, so patrols at the schools are being beefed up today by officers in uniform and plain clothes.