i watch a TV reality show on A&E "Live PD" which follows police departments and shows video of the officers.
It seems often that one officer shows up first, and then may call for back up,
or back up arrives a few minutes after the first.
"Live PD is hosted by Dan Abrams, the chief legal affairs anchor for ABC News. The program features live video feeds from multiple (currently eight) law enforcement agencies throughout the United States. The departments include the Lafayette Police Department, Lawrence Police Department, Missoula County Sheriff's Office, East Providence Police Department , Richland County Sheriff's Department, Salinas Police Department, Tallahassee Police Department, and the Tulsa Police Department.
Abrams is joined in-studio by two co-analysts: former Washington, D.C. special police officer and crime reporter Tom Morris Jr. and Sgt. Sean "Sticks" Larkin of the Tulsa PD. Occasionally, the trio are joined by an officer that has been featured on the show in the field."
https://en.wikipedia.org/wiki/Live_PD#Overview