The document you posted.
This witness saw Cruz and radioed someone. When the shooting started this witness radioed a "code red" meaning a school emergency. That doesn't sound like LE jargon. And after Cruz was detained this witness was brought to the scene to ID him as the person this witness saw entering the building with the bags.
I conclude this witness is not Peterson who was reported to be somewhere else when the gunfire stated.
Also, the term “co-worker” doesn’t sound like a fellow police officer.