Montreal police have arrested a man they believe "participated actively" in the fatal shooting of Meriem Boundaoui, a 15-year-old girl whose death helped put a spotlight on the issue of gun violence in and around the city.

Salim Touaibi, 26, was arrested Monday morning, according to Comm. Salvatore Serrao, a spokesperson for the Service de Police de la Ville de Montréal (SPVM).

"This arrest does not mean that the police investigation is over. We know that the suspect who was apprehended was not alone," Serrao told reporters during a news conference Monday afternoon.

He would not confirm if police believe the accused fired the shots that killed the 15-year-old.

Touaibi was already detained for alleged offences related to drugs and gun possession when he was arrested for Boundaoui's death, Serrao said.

The accused was formally charged with first-degree murder and four counts of attempted murder during an appearance at the Montreal Courthouse Monday afternoon. Members of Boundaoui's family were also there.

Boundaoui was killed on Feb. 7, 2021 while she sat in the passenger seat of a parked car near the corner of Jean-Talon and Valdombre Streets. It's thought she was not the target of the attack. Boundaoui was one of several teenagers killed in Montreal in the last 18 months.

In announcing Monday's arrest, Serrao said the SPVM's number one priority is fighting armed violence. He also issued a warning to those responsible for recent shootings and other acts of violence.

"Criminal investigations are sometimes long and complex, but know that our investigators are determined," he said.

In a tweet, Montreal Mayor Valérie Plante applauded the SPVM for its work.

"Rest assured that we are working hard to keep Montreal safe and prevent crimes like this," Plante tweeted. "And our efforts are bearing fruit."