LAC-MEGANTIC, Quebec — Burkhardt said the train's engineer had been suspended without pay and was under "police control."
Investigators also had spoken with Burkhardt during his visit, said a police official, Sgt. Benoit Richard. He did not elaborate.
Until Wednesday, the railway company had defended its employees' actions, but that changed abruptly as Burkhardt singled out the engineer.
"We think he applied some hand brakes, but the question is, did he apply enough of them?" Burkhardt said. "He said he applied 11 hand brakes. We think that's not true. Initially we believed him, but now we don't."
Burkhardt did not name the engineer, though the company had previously identified the employee as Tom Harding of Quebec. Harding has not spoken publicly since the crash.
"He's not in jail, but police have talked about prosecuting him," Burkhardt said. "I understand exactly why the police are considering criminal charges ... If that's the case, let the chips fall where they may."
Investigators are also looking at a fire on the same train just hours before the disaster. A fire official has said the train's power was shut down as standard operating procedure, meaning the train's air brakes would have been disabled. In that case, hand brakes on individual train cars would have been needed.
The derailment is Canada's worst railway disaster since a train plunged into a Quebec river in 1864, killing 99.
Quebec police have said they were pursuing a wide-ranging criminal investigation, extending to the possibilities of criminal negligence and some sort of tampering with the train before the crash. The heart of the town's central business district is being treated as a crime scene and remained cordoned off by police tape.
At a news conference shortly before Burkhardt's arrival, Quebec Premier Pauline Marois faulted his company's response.