LAC-MEGANTIC, Quebec -- Canadian authorities have found evidence that the oil train was tampered with before it derailed and exploded, according to CNN.
Quebec police inspector Michael Forget said Tuesday that investigators have "discovered elements" that have now led to a criminal probe. The crash in Lac-Megantic on Saturday killed at least 15 people. He said 35 people are still missing.
Forget did not give details in Tuesday's news conference but ruled out terrorism as a cause.
Firefighters put out a fire on the same train shortly before it crashed. Investigators are working to determine whether that fire set off the deadly chain of events.
Ed Burkhardt, CEO and president of Rail World, the parent company of the Montreal, Maine & Atlantic Railway, has said there's evidence the engine powering the brakes was shut down at some point.
Pressured by Canadian media outlet CTV, Burkhardt wrote Tuesday in an e-mail exchange, "We are now aware the firefighters shut down the locomotive. By the time (Montreal, Maine & Atlantic) people found out, it was too late."
The subsequent explosion destroyed about 30 buildings and forced a third of the 6,000 residents from their homes.
CNN and the Associated Press contributed to this report.