MONTREAL — Canadian police used the BlackBerry messages of suspects in the assassination of a New York mafia boss to crack the case, a Montreal-based newspaper reported Thursday, citing "several sources."

Five suspects in the killing of mobster Salvatore Montagna, who was gunned down in November and had criminal links in Canada and the United States, were arrested last month.

Incriminating messages sent by one of the suspects, Vittorio Mirarchi, a businessman with alleged ties to the mafia, led to the arrests, the La Presse newspaper said.

Blackberry's purportedly unbeatable encryption capability is coveted by businessmen and politicians for its secure communications.

But various authorities around the world have also demanded access from manufacturer Research In Motion to BlackBerry communications to thwart alleged criminal and terrorist activities and intercept messages for other reasons.

The suspects in the Montagna murder were reportedly surprised to learn that Quebec police had accessed their private communications, the paper said.

Police would not say whether they cracked BlackBerry's encryption or RIM gave them access to its secure servers.

Meanwhile, RIM issued a standard operating statement noting that it defends the legal privacy rights of users in the countries where it operates.