Làm Ơn Dịch Giúp!!!

[LtDra]

Would you please help me to translate " requesting back up" into Vietnamese?
(I heard it in the movie when the policeman shouted while he was chasing a guy.)
What word should I use at blue part?
Thank you!

Here are some suggestions may help.

I heard the policeman yelled/shouted "requesting back up" while he was chasing (after) a guy in the movie that I had watched.

or

I heard "requesting back up" which was a policeman yelled/shouted while he was after a bad guy in the movie that I had watched (last night).