Officers from the U.S. Marshals Service's Fugitive Task Force
went to the motel in Topeka on Saturday night to look for Orlando J. Collins, the FBI's Kansas City office said. Collins, 28, was wanted on two robbery-related charges.
But as officers reached the motel room door, "they came under gun fire from inside the hotel room," the FBI said in a statement.
Two deputy U.S. marshals and an FBI agent were shot but are expected to survive, the FBI said.
Previously, Topeka police said a fourth federal agent had been injured in the melee. That officer apparently suffered a leg injury but was not shot, the FBI said.
Gunfire leads to actual fire
As the shooter kept firing from the motel room, "a fire was ignited from within the room, which eventually spread to the entire building," the FBI said.
That blaze burned for more than three hours as flames soared into the night sky, CNN affiliate WIBW
Authorities later found an unidentified body in the room Collins was believed to be in, the FBI said.
No one else was injured, since the hotel had been evacuated.
A dangerous operation
Collins was on Kansas' most-wanted list and considered armed and dangerous, the FBI said. A federal arrest warrant charged him with two counts of interference with commerce by means of robbery.
Some nearby residents initially thought the gunfire from the motel might have been firecrackers.
"We were wondering what exactly what it was," Christian Brull told CNN affiliate KSNT
. "There was a couple of shots going on."
Lindsay Haight and Emerson King told the station the gunfire came very rapidly.
"Fully automatic weapon, for sure, it sounded like," King said.