Quebec provincial police have concluded their investigation into last July's rail disaster in Lac-Mégantic and have turned the file over to the public prosecutor's office, a police spokesman said Monday.

Forty-seven people were killed in the explosion that resulted from the derailment of a train carrying oil.

"The investigators of the Sûreté du Québec have sent the investigation report to the director of criminal and penal prosecutions," spokesman Claude Denis said.

Neither he nor the prosecutor's office would give details on what was in the report, or say whether, or when, criminal charges might be laid.

The news agency QMI reported over the weekend that an unidentified police source said police were confident prosecutors would lay criminal negligence charges.

The disaster occurred after a single engineer parked his train for the night on a main line uphill from the small town of Lac-Mégantic. The train of oil tankers started rolling and eventually derailed, with several tankers exploding into balls of fire and flattening the centre of the town.

The train was operated by U.S.-based railway company Montreal, Maine & Atlantic (MM&A).

Contacted by Reuters, MM&A Chairman Edward Burkhardt said he has been in touch with investigators "from time to time" to provide requested information, but that he did not know about any pending charges related to the crash.

"I have no information about them… I have no comment, I have nothing to comment on," he said.

Jean-Pascal Boucher, spokesman for the prosecutor's office, said the prosecution has been working with the police since the accident and that it is continuing to analyze the evidence.