Two assaults early this week have led police in Lehigh County to beef up security at Northern Lehigh High School.
Police say threats made on Facebook had some parents and students concerned about safety.
"I wanted to reassure the students and the parents that we're going to do everything we could to ensure their safety," said David Rachman, chief of the Slatington Police Department. "Obviously nobody can be 100 percent safe."
Investigators say the situation started with an assault in Walnutport Borough earlier this week.
Another person was assaulted in Slatington Borough then threats started to appear on the social media site Facebook.
Some threats indicated the group may be a gang.
"At this point, I think it's a loose association of friends that got together," added Rachman. "Definitely there appears to be two separate factions involved here."
Around 50 students met with police after the first class period Thursday.
Those with parental permission went home early.
"Kids wanted to get out of the school because they were afraid something was going to happen. So I went up to address the students and the parents," said Chief Rachman.
Investigators say three juveniles have been arrested.
They say more people may be taken into custody as well.
"We're not going to let this thing go until we've got everybody charged that we can charge with this," said Rachman. "We're not going to fool around with this."
Slatington Police and two state police officers will be providing extra security at the school until it is no longer needed.