Factual error: When Malcolm is talking on the telephone in an extreme close up, you can see the connector on the phone is one of the modern snap-in modular jacks. Telephones in the 1960's did not have those.
Factual error: Malcom X yells for 911 in the movie, however at this time 911 didn't exist as an emergency number. The first ever 911 call was placed in 1968.
Answer: It was Rudy who called the police. He was double crossing his partners and making off with the loot from their crime spree.