OTTAWA—A federal judge blames “institutional and systemic negligence” for the latest instance of Canada’s spy service failing to be sufficiently forthcoming about applications for judicial warrants to conduct investigations. In a decision made public Tuesday in redacted form, Federal Court Justice Henry Brown said the Canadian Security Intelligence Service breached the duty of candour it owed to the court in certain October 2018 warrant applications. The spy service had applied for several warrants to intercept the communications of a “group of individuals” deemed a threat to the security of Canada, the specifics of which were excised from the public version of the ruling. Brown found CSIS failed to disclose that human source information relied upon to obtain the warrants might have flowed from potentially illegal activities. He also faulted the spy service for not revealing information that had the potential to reflect adversely on the reliability and credibility of the …