Simplify the following text for a Grade 4 native English-speaking person.
Original: Collins was killed in the subsequent gun battle , which lasted about 20 minutes , from 8:00 p.m. to 8:20 p.m. .
Simplified: Collins was killed in the gun battle , which lasted about 20 minutes , from 8:00 p.m. to 8:20 p.m. .