Montreal police are searching for an important witness they believe is linked to two criminal fires that happened in early September in the Mercier-Hochelaga-Maisonneuve borough.

The first fire broke out on Sept. 1 at about 11:50 p.m., behind a rental building on Ste. Catherine St. E.

The second occurred on Sept. 3, around 12:30 a.m, in a recycling bin on Darling St., very near the site of the first fire. This one caused an explosion.

In both cases, investigators found a propane cylinder normally used for welding they said was to ignite the flames. On Sept. 5, police say they found a shoulder bag containing an incendiary device near the site of the two events. They believe it is linked to the pair of arsons.

Investigators retrieved images of the witness wearing the shoulder bag when buying these propane cylinders.

In images from Sept. 1, the man wore a long-sleeved grey sweater, blue pants and dark shoes with white soles. In images from Sept. 2, he wore a blue ¾-length coat, camouflage pants, a black cap and glasses.

Anyone with information on these fires or the witness should contact 911 or Info-Crime Montreal at 514 393-1133 or online. The information will be treated anonymously and confidentially.