University Park police said seventh threat was directed toward Highland Park High School Monday.
Officials said Monday's threat was sent to Crime Stoppers via email.
Police conducted a search of the school and found nothing.
School administrators elected to not lock down the campus or interrupt classes.
Three times in January, threatening notes were found on campus. Two more notes were found last week, as well as .22-caliber bullets.
The Highland Park school district said last week they plan to continue to have an added police presence until it feels it is no longer needed.
There is a $10,000 reward for information leading to the arrest and conviction of the person responsible for the threats.