Police could lose a valuable tool in hunting child pornographers if a Supreme Court decision goes against them on Friday.

Matthew Spencer of Saskatoon wants Canada’s highest court to throw out his conviction for possessing child porn because he argues police violated his constitutional rights when they tracked him down by asking his Internet provider for his name and address without a warrant.

“An individual would expect the records of his Internet provider and his identity to be kept confidential and private,” his lawyers told the court.

In 2007, Spencer, 19 at the time, used the program LimeWire to obtain and share child porn online. Investigators with Saskatoon Police traced the file sharer to an IP address and under the Personal Information Protection and Electronic Documents Act (“PIPEDA “), asked Shaw Communications for help in identifying the subscriber.

The contract belonged to Spencer’s sister and the telecom company provided her name and address. Police then obtained a search warrant, learned her brother lived there and seized his computer.

They discovered that, at one point, he had 441 still images and 112 videos on his shared folder. “What the images were portraying were disgusting, demeaning, depraved activities of child abuse of the worst order,” the Saskatchewan trial judge said in convicting Spencer.

The lower courts ruled the young man had no expectation of privacy when Shaw’s user policy, posted on its website, warns customers that subscribing to their service means consenting to the release of such information: “You hereby authorize Shaw to cooperate with law enforcement authority in the investigation of suspected criminal violations, such cooperation may include Shaw providing a user name, IP address or other identifying information.”

Spencer’s lawyers argue that Shaw needed a warrant from a judge, and not a simple letter from the police.

“It had no authority to waive (his) Charter rights. It could not any more legitimize the police seizure than could hotel clerks or landlords by unlocking a suite for the police without a warrant or a telephone service provider allowing police to listen in on telephone calls without authorization,” argued lawyers Aaron Fox and Darren Kraushaar. “It bowed to the demand of the state without question.”

Spencer’s legal team warned that the police can’t be trusted to access private information from a telecom without pleading their case before a judge. “As we move towards a time when virtually every aspect of our personal life is found on our computer, the need for judicial authorization to access that information is more important than ever.”

The Crown and interveners from several other provinces urged the Supreme Court to uphold Spencer’s conviction, saying the police did little more than ask for basic “tombstone data” - the bare bones of name, address and telephone number which are hardly considered private.

“Names and addresses are largely innocuous, known to most everyone with whom we deal in society,” the Crown argued. “They are in the telephone directory. The licensors of our vehicles, our employers, and the schools we attend know them. Our neighbours know us.”

That kind of basic information shouldn’t need a judge’s signature, the Crown insisted. What does require a judicial sign off - and which the police received - was a warrant to then search that address.

The lawyers for Ontario’s attorney general say police get this basic information all the time: When they suspect a bank account was used for money laundering, the bank may give them a name and account number to help their criminal investigation. When a rental car is spotted in a drug deal, the rental company can give police the contract and driver’s name and address to follow-up.

When someone uses a public file-sharing program to obtain and distribute child pornography on their computer, their internet service provider should be able to give that subscriber’s name to police. As Ontario’s lawyers argue: “When the files on offer are images of child abuse, the public expects no less.”

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