The Inn on the River (1962)
A serial killer named The Shark is terrorizing London by killing his victims with a speargun and then, dressed in a scruba-diver's wetsuit, using the city's sewer tunnels to make his getaway.
A serial killer named The Shark is terrorizing London by killing his victims with a speargun and then, dressed in a scruba-diver's wetsuit, using the city's sewer tunnels to make his getaway.