A volunteer at a beloved no-kill Brooklyn animal shelter filed a lawsuit accusing the nonprofit of shipping unadoptable dogs to their deaths down south to make way for profitable puppies. The explosive allegations against Sean Casey Animal Rescue were included in a small claims suit filed by Dana Paoli, who’s trying to claw back a $1,000 donation he made to SCAR after the death of Gunther, a pitbull mix who was euthanized in Arkansas over “aggressive” behavior. But volunteers say the 3-year-old white canine was more Clifford than Cujo and was sentenced to death for taking up kennel space. Gunther was euthanized last month due to “aggressive” behavioral problems. Facebook/Sean Casey Animal Rescue¿ “He was super-duper friendly. He wanted to meet everybody. The only real problem I had walking with him was that every single person we passed, he wanted to say ‘hi,'” said Paoli, a volunteer who estimates he spent over 200 walks with the “little snuggle cuddle bear” during its one-year stay at SCAR.…