Image 1 of 5 ▼ K-9 Zeus | Crystal Lake policeThe Brief Crystal Lake police are mourning the loss of K-9 Zeus, who died over the weekend from a sudden medical emergency caused by cancer. The department praised Zeus as a loyal and courageous member of the force and offered condolences to his handler and family. The Crystal Lake Police Department is mourning the loss of K-9 Zeus, who died over the holiday weekend following a sudden medical emergency caused by cancer. What we know:Zeus passed away Saturday, according to a statement released by the department. The Algonquin Police Department, which worked alongside Zeus on numerous occasions, also issued a statement recognizing his service.