This cafe was hit by a Molotov cocktail on Nov. 24. (CBC)Montreal police made nine arrests Thursday in connection with a series of café firebombings.

Five men were arraigned at the Montreal courthouse in connection with attacks on two Montreal cafés last fall.

Four others, including one minor, were held for questioning.

The charges of arson, mischief and conspiracy are related to attacks on the Peaches Bar and the Pirandello Café on Oct. 28.

Molotov cocktails were thrown through the windows of the establishments in the city's east end.

So far, investigators have solved five of 18 attacks against Italian-owned cafés in the city's east end which took place between September and January, police said.

The suspects arrested as part of a sweep called Project Arcane are all known to police and known to be connected to street gangs, said Montreal police Insp. Bernard Lamothe.

Investigators are still working on different theories for the attacks, including that they could be related to the fatal shooting of Nick Rizzuto Jr., the son of the presumed head of the Montreal Mafia, in December.

"All of these theories are still very plausible even today after these arrests," said Lamothe. "It can be either street gangs that want to take more territory for selling narcotics [or] it can also be inside of the mafia."

The suspects include Yann Bouthillier, 30, Louis Cyr, 25, Lukenson Desgraves, 26, Sébastien Calixte, 22, and Jean-Sébastien Jacques, 24.

Cyr and Desgraves were released on bail and ordered not to communicate with known street gang members.

'It can be either street gangs that want to take more territory for selling narcotics [or] it can also be inside of the mafia.'—Montreal Police Insp. Bernard Lamothe

The Crown objected to the release of the other men, including Calixte, who made headlines last week after confessing to the murder of a rival street gang member.

He made the claim while appearing as a witness for the defence in the murder trial of Whoody Aristilde, arguing that he wanted to clear his conscience.

Aristilde, also 22, was accused of premeditated murder in the shooting of Gabriel Dominique, 24, in the parking lot of a Montreal flea market in 2007.

However, the jury in the case agreed with the Crown's argument that Calixte's confession was unreliable and on Saturday, found Aristilde guilty.Sbastien Calixte, 22, is one of six men charged in connection with the attacks. (CBC)

A 10th suspect in the arson attacks, Mickendy Demosthène, 20, was arrested in December.

He is scheduled to have a preliminary inquiry on Aug. 30.

Last month, officials released surveillance videos showing two of the attacks, in hopes of getting information from the public.

One of the people arrested on Thursday is one of two men who can be seen on the footage, police said.

The investigation into the firebombings continues, prosecutors said.