The Montreal police (SPVM) arson squad is investigating after an accelerant was found and a suspect was spotted before a fire in a commercial building in the Old Port.

Emergency services responded to a call about a fire in a commercial building at around 2:35 a.m. on de la Commune St. West and Saint Dizier.

By the time police arrived, firefighters had quelled the fire.

When examining the blaze, firefighters found an accelerant and transferred the file to the SPVM's arson unit.

"A possible suspect was seen just before the building was set on fire," said SPVM spokesperson Mariane Allaire Morin.

There were no injuries in the fire, and no suspect has been located.

The investigation continues.