YAPHANK - K-9 units are considered critical instruments in the hunt for evidence in the Gilgo Beach murder investigation, but training a police dog is a process that takes years of hard work, practice and patience. During their training, the dogs are given exercises to find hidden items or track down people - tasks that trainer Ralph Fuellbier says the dogs perform in minutes, but could take hours for humans. Suffolk County uses about two dozen dogs, all of them German Shepherds imported from Europe. They go through basic training before moving on to specialty training, such as sniffing out narcotics, bombs, or cadavers. One of the Suffolk County police dogs managed to find the human remains along Ocean Parkway despite rough terrain and dense vegetation."The dogs were a tremendous tool," says Stuart Cameron, the commanding officer of the K-9 unit.The average career of a police dog is about seven-eight years. The Suffolk County Police Department says the animals are allowed to retire when they're still in good health. They spend the rest of their lives with the handler that they worked with.