MUSTANG, Oklahoma - Administrators placed Mustang North Middle School on lockdown after a threat was found written on a bathroom wall.
In a letter to parents, administrators said the threat was found in a boy's bathroom on Saturday.
The school was placed on lockdown Monday and additional security measure will be in place this week.
"We do not believe the message has any credibility," the letter reads. "However, we take all threats seriously."
No backpacks or large purses will be allowed for the remainder of the week and access to the hallways and restrooms will be limited.
Two Canadian County Sheriff's deputies are assigned to the north side of the suburban district. They are assisting with the investigation and will maintain a presence at the school.