MONTREAL -- A Montreal-based architecture firm involved in the construction of an immigrant detention centre says it has been attacked again by "extreme leftists."

The firm Lemay said in a statement one of its employees was "personally targeted" in front of his home. The company added its property has been hit several times in recent months by the leftist group, which it doesn't name.

While Lemay did not say who was attacked or how, an anonymous post to an anarchist website described an arson attack against the car of one of the firm's architects and partners. The post on Montreal Counter-Information celebrates the torching of a BMW belonging to a Lemay partner outside his home in the city's west end on June 11.

"May fires burn for all that the worlds of prison and borders have stolen from us," the post reads.

Montreal police spokesman Julien Levesque confirmed Wednesday the force's arson squad is investigating a June 11 arson incident involving a car in the Notre-Dame-de-Grace borough. He wouldn't give other details.

In its statement, Lemay said the firm "always places the human at the heart of our creations. We would like to remind you that our mission is to create quality environments, and our project of the new Laval Immigration Center is no exception."

It added: "Although we have been attacked ... by the criminal actions of an extreme leftist group on numerous occasions in recent months, the situation has taken a most unacceptable turn as one of our associates has been personally targeted in front of his home."

The company referred all other questions to the Canada Border Services Agency, which will be responsible for running the Laval facility. An agency spokesperson was not immediately available for comment.

According to the federal government's procurement website, Lemay is part of a joint venture that received a contract in 2018 worth up to $5 million for a new immigration holding centre in Laval, north of Montreal. Since then, the company has been the target of a series of attacks.

Last May, police opened an investigation after crickets were released into Lemay's offices. A group calling itself the Anti-construction Crew claimed responsibility on the Montreal Counter-Information website.

A poster available for download on the website shows a group of mice holding wire cutters, spray paint and an incendiary device, in front of a sign reading "Lemay Architecture Condos."

The poster says that on March 19 the windows of the sales office of a condo tower in Montreal were smashed and another condo development in the city was "redecorated" with spray paint.

"What do these condo developments have in common?" the poster asks. "They were both designed by the Lemay architecture firm, which is helping to build a migrant prison in Laval, Quebec .... Fire to the prisons! Sabotage borders, their enforcers, and collaborators!"