The arrests were made in different Quebec cities in an operation that involved five police forces — the RCMP, the Surete du Quebec, and three municipal forces.
Those arrested faced a variety of charges Tuesday, including mischief, conspiracy, and unlawful use of a computer. Three of them were minors. The arrests took place in Rimouski, Sherbrooke, Forestville, Montreal and Longueuil, Que.
Police offered no other clues about the case, other than to say the attacks were on "public" and "parapublic" websites. They said they did not want to jeopardize their ongoing case by sharing details, such as whether those arrested operated under the "Anonymous" name.
Cyber-activists have, under the group name "Anonymous," mounted numerous campaigns in different countries and on occasion defaced websites of organizations they oppose. A recent target has been the Quebec government because of its anti-protest law.
Self-described Anonymous activists have recently hacked into a variety of websites linked to the Quebec government — including the province's education and public-safety departments, as well as that of the provincial Liberal party.
But police Tuesday did not specifically link the arrests to Anonymous. They also did not specify what websites those arrested were accused of attacking.
"Police authorities want to indicate that they take this kind of crime very seriously," the police said in a statement. "They will use every means at their disposition to find the authors. These people expose themselves to criminal charges, regardless of whatever intention prompted their action."
Last month, hackers managed to disable more than a dozen websites, including the sites of the Education Department, the Quebec Liberal party and the Montreal police force.
The circle then appeared to broaden. In addition to Formula One car-race spectators having their information published online, footage was released from an exclusive birthday party held for a member of the powerful Desmarais family.
People claiming to operate under the name "Anonymous" sent an ominously worded email to more than 100 people who bought tickets to the Formula One Grand Prix weekend in Montreal.
"If you intend to use a car, know that your road may be barricaded," said a document described as a ‘Notice to Grand Prix Visitors.’
"If you want to stay in a hotel, know that we may enter it. If you seek to withdraw money from a bank, know that the shattering glass may sting. If you plan on watching a race, know that your view may be obscured, not by exhaust fumes but by the smoke of the fires we set. Know that the evacuation order may not come fast enough."
There were protests at a number of sites related to the June 7-10 Grand Prix, and attempts to paralyze some of them, but police acted pre-emptively. Over that weekend, they either created barriers blocking access to certain public places, or detained people suspected of planning to disrupt events.
The police reaction brought a counter-reaction from protesters and their supporters: that law enforcement violated fundamental freedoms, such as the right to free mobility and expression, by making arbitrary detentions in what amounted to "political profiling."