Two Meridian high schools have cancelled assemblies planned for Friday and police will have an increased presence in at least one high school on Friday following an unsubstantiated threat that something bad would happen at a Meridian high school on Friday.

Meridian school district spokesman Eric Exline said rumors started circulating among students on Monday that something bad was going to happen during an assembly at Centennial High School on Friday, but it wasn’t clear what was going to happen.

In the last 48 hours, the communications increased and the threat has evolved to include references to a gunman and additional schools — Rocky Mountain, Mountain View, Meridian and Eagle high schools.

The majority of the threat-related communication has taken place through text messages and social network sites. “Somebody got a text message from somebody saying they heard something bad was going to happen,” said Meridian school district spokesman Exline said.

Officials have been trying to trace the messages to find the original source, but have not yet found it.

Exline said school officials and police decided to take extra precautions, including canceling Friday's assemblies at Centennial and Mountain View.

On Friday, Boise police will be on site at Centennial, which is a Meridian school but located in Boise.

For the other high schools on Friday, each school’s assigned resource officer will be more visible and Meridian police, which had already increased patrols around schools following last week’s mass shooting at an elementary school in Newtown, Conn., may add even more patrols.

Boise school district does have school on Friday.