Last week the watersports lake at the Sandwell Valley country park in the West Midlands was closed as experts set out to snare a 3ft-long creature spotted by anglers.
Wildlife rangers now believe, despite earlier speculation that they were on the trail of an alligator, that their quarry could be a salamander, a cold water lizard from the Appalachian mountains in North America.
The park's senior countryside ranger, Ray Crouch, who has led the search, said: "It hasn't been sighted for a couple of days now but we have come to the conclusion that it is a North American salamander, exotically known as a `hell bender', which is endangered in the wild and could have arrived in this country via the pet trade."
The sightings led to a number of people trying to capture the creature. A rescue boat attendant, Ricky Downes, said: "At about 1am on Thursday we had about 30 people down here with torches, pikes and nets trying to catch the thing. We also had some guy who said he was an ambassador or diplomat who offered to catch it, saying he had caught several alligators in his home country."