Emil and the detectives (1964)

When Emil travels by bus to Berlin to visit his family, his money is stolen by a crook who specializes in digging tunnels. While following the thief, Emil runs into Gustav, a young boy who gathers up all his friends to help Emil find the money. However, they get into more trouble than they bargained for when Emil's pickpocket turns out to be mixed up with a couple of notorious bank robbers.