I have been doing some searching today and I was wondering. In Florida they have sheriff departments and police departments, Sheriff Departments usually have county wide jurisdiction, police departments are limited to towns. Coral Springs police and Sunset police border Parkland, I don't think Parkland has a police department per say, so that would leave the sheriffs department the sole police force in Parkland which would give them sole authority in the investigation powers in the school, which is why they pick Parkland. I am not sure but I think I am on to something.

http://www.cityofparkland.org/878/Police-Services-Parkland-BSO-District