School police arrested three teenagers in the fight that happened hours before the shooting, Sheriff Doug Gillespie said. Investigators were still seeking two gunmen, who were believed to have fled on foot from the scene of the shooting, a working class neighborhood of northeast Las Vegas.
Authorities would not release any other information about the two victims who were still hospitalized late Tuesday, including whether they were students or had been on the bus.
Earlier Tuesday police had said all the wounded were on the bus.
Gillespie called the bus stop shooting "a carryover from what took place. This is not a random act."
Archie Gorai, 22, who lives about a block from the site of the shooting, said he heard about eight gunshots while he was wrapping Christmas presents at his home.