CHICAGO (CBS) — Parents plan to gather outside Whitney Young High School on Wednesday, in a show of solidarity, after two threatening messages were found scrawled on bathroom stalls in the past few days, prompting heightened security measures.

Whitney Young will have extra security in place, after threats that said, “you will all pay 12/5.” The first threatening message was found Friday in a boys’ bathroom. A similar message was found Tuesday in a girls’ bathroom, after school officials announced plans for more security on Wednesday.

All students will pass through metal detectors at the entrances, all bags will be subject to search, and students must wear IDs around their necks all day. Extra police officers also will be on duty at the school.

“We’ve increased our patrols in that area, and have added some additional school resource officers. We take everything seriously until there’s a reason not to,” Police Supt. Eddie Johnson said.

The school will be placed on soft lockdown, meaning once students go inside for class, they won’t be allowed to leave the building until the end of the day. Students must use the bridges connecting the two buildings, rather than going outside.

Any student caught outside the school after classes begin, or opening school doors for anyone else – including their family – will receive an automatic one-day suspension.

The Friends of Whitney Young group has invited parents and guardians to gather outside the school at 7:30 a.m., in a show of support for students.

“Our children, both here and across the nation, have experienced too much sadness and uncertainty due to violence or threats. In a sign of solidarity for our own children, and for every child and family touched by fear and hate, we will stand together,” the group stated in a message to parents.