More than two years after an explosion and fire killed two people and tore through a Woodstock apartment building, the Ontario Fire Marshal (OFM) has been called back in to help investigate.

On March 27, 2011, the 45-unit Victoria Street apartment building was hit by an explosion.

The bodies of Margaret Gillett, 73, and Bill Watmough, 79, were found buried in rubble several days later, while nearly 100 people were displaced from the building.

The investigation into the fire was passed to OFM forensic fires, who handed the file back to Woodstock police earlier this year.

After interviewing and re-interviewing witnesses, police announced Wednesday that they had called back the OFM to re-examine the cause of the explosion.

More forensic testing will take place, but police say they don’t know how long the testing will take.

Police say there has been no evidence uncovered to suggest any criminal activity causing the explosion.

A freedom of information request from CTV News for the Fire Marshal’s report was denied on May 31, on the grounds that the explosion remains an ongoing police investigation.