UPDATE 3:30 p.m. Friday:
NBC News is reporting that Addison police said a girl was found restrained in a school restroom. No students were harmed and the intruder was not found, police said.
UPDATE: 1:45 p.m. Friday:
NBC News is reporting that Addison police have issued an all-clear at Indian Trail Junior High School. A briefing is expected at Addison City Hall. This is the fourth lockdown, and the first hard lockdown, at the school in the past month, according to the NBC News report.
UPDATE: 12:08 p.m. Friday:
Police dispatch information received at 11:50 a.m. suggests the lockdown may involve a suspected sexual assault. Suspect is described as a male white dressed in all black and wearing gloves. K-9 and helicopters are searching the area.
An Addison junior high school is on "hard lockdown" after an intruder reportedly entered the building. About 1,300 students are being held inside their classrooms.
Addison police are providing no information yet on what is happening at Indian Trail Junior High School, the Chicago Tribune reported at 11:30 a.m. Friday.
The school is located at 222 Kennedy Drive in Addison.