School officials at Legacy High School in Broomfield found an ominous message Monday written on a student's desk threatening a shooting, Broomfield Police confirmed to 9NEWS.

9NEWS obtained a copy of the letter Principal Sara Marx sent home to parents letting them know of the threat. School officials said they believe it was written during second or third period Monday and simply said, "school shooter tomorrow."

The school has been investigating similar statements since early last week. After that incident, the school sent that student home and police questioned him or her; that student is still out of school as authorities investigate the newest threat.

As a precaution, Broomfield Police said they'll have an increased presence at Legacy High on Tuesday.

Students and parents are encouraged to contact a trusted adult at the school or Safe2Tell if they know anything about the incident.

You can anonymously report tips to Safe2Tell by calling 1-877-542-SAFE.