Can anyone identify this TV series? I remember it was broadcast sometime in the early to mid 80s in the UK but I can't recall which channel.
It was set on a sparsely populated remote island or coastal region of the UK. Isolated individuals started turning up killed and mutilated, the bodies featured peculiar injuries such as unidentified bite marks. One character muses that the bites suggest a mouth similar to the beak of a tortoise, although larger than any known species. As the story progressed some clues came to light among the possessions of a victim found in his trashed tent. The occupant had been using a tape recorder which recorded the attacker's growls and victim's screams, as well as a camera that was triggered during the mayhem, capturing partial images of what looks like a creature with either a dark carapace or strange clothing. Later a small craft of futuristic design is discovered on a beach, prompting speculation that the creature is an extraterrestrial. Eventually an encounter with Soviet military reveals that they had been conducting tests of a revolutionary submarine design which involved physical and mental integration of the pilot. The craft malfunctioned or was involved in an accident and this sent the pilot on a psychotic rampage.
The series might not stand so well if seen today but at the time it was quite enthralling. I particularly appreciated how each revelation altered the genre, from murder mystery to horror to science fiction and, ultimately, tragedy. If I can't see it again at least I could find out if those responsible went on to produce more work of interest. Thanks for any help.