The Salt Lake County Sheriff's Office stepped up its visible and undercover presence at Skyline High School on Monday after a janitor recently found a threat scrawled on a boys bathroom wall.

The threat was written on the wall with a marker and was quite lengthy and large, Lt. Don Hutson said. The message suggested a threat to hurt some students but didn't target anyone directly, Hutson said.

Granite Police Department asked the Sheriff's Office to look into the threat Monday to find out who wrote it. The threat was found in one bathroom last week. Hutson did not know if they are looking at one person or a group that made the threat.

School officials reached out to parents Tuesday via its voice messaging system in an effort to "stymie rumors" and reassure them of their childrens' safety, said Granite spokesman Ben Horsley.

"If we felt student safety was jeopardized, we'd consider closing the school," Horsley said, noting that police are "pursuing good leads."

Hutson said police have yet to determine whether the threat is serious or a hoax. But the extra police patrol will continue for a while, he said.