Revealing mistake: When the terrorists drop the dead body out the aircraft door, look closely at the aeroplane just beneath the door, you can see the reflection of the mat the stuntman lands on, as well as the spotters around it.
Revealing mistake: When Rane jumps out of the hospital window and crashes through the umbrella, table, and people, you can see him land on an air mattress. Even though it's camouflaged to match the ground, you see it deflate under his weight.
Answer: I just rewatched it this morning. When Rane is trying to persuade Sheriff Biggs that he means business, one body (presumably The Captain) is thrown out of the plane. Just before the passengers are released, we see a quick shot of yo ambulances. One has 3 full occupied body bags in it. Therefore, it's implied the other two are in the other ambulance. This takes place before the FBI guy gets there. The fact that he tells Rane, those guys you killed were my friends" means that at some point they were identified by name. He could've found out numerous ways (Washington told him, briefing, the paramedics, Biggs, etc).