"We are executing a search warrant," Sergeant Benoit Richard of the provincial police, Sûréte du Québec, told Reuters. "We are searching the offices now."
Richard said officers were combing through the railway's office in Farnham, Que., about 65 kms east of Montreal, in search of evidence that could help with their investigation into the July 6 tragedy.
Montreal Maine and Atlantic (MMA), a unit of Chicago-based Rail World, operated the train that crashed into Lac-Megantic.
The train, which was hauling 72 tanker cars full of crude oil, and was operated by a single engineer, had been parked for the night on a main line uphill from the lakeside town. After the engineer left, it started rolling downhill, derailed in the center of Lac-Megantic and exploded into a wall of fire.
MMA Chairman Ed Burkhardt was not immediately available for comment on July 25. In the days after the crash, he publicly questioned whether the engineer had set enough brakes to hold the train in place before he left for the night.
Investigators are still searching the center of Lac-Megantic for clues on the cause of crash. They have said the train's hand brakes are one focus of their probe.