Men at Work (1990) on Netflix

Carl and James are two pleasant but unambitious garbage men. Carl has a telescope with which he observes his neighbors. One evening he sees a man giving a female neighbor a hard time. As she leaves he shoots the man with a pellet gun. Hiding, he and James miss two men strangling the man and leaving with the body. When he appears in a can on their route they are afraid and hide the body, fearing that they may be implicated in the death. Trying to crack the case, they spy on the woman, join up with a slightly to majorly crazed Vietnam vet, kidnap a pizza man and help to protect the ecology.