Beavers are to be legally reintroduced in a test project next year
A beaver found dead on a beach in the Highlands suffered a "cruel" death after ingesting a large quantity of sea water, police said.
Its body was discovered at Eathie on the Black Isle in April.
Northern Constabulary's wildlife crime officer, Ch Insp Paul Eddington, said its release and cause of death were being treated as a cruelty matter.
He said it was suspected the animal was linked to illegal releases of beavers in other parts of Scotland.
Ch Insp Eddington told the BBC Scotland News website: "Our inquiries are still ongoing.
"Beavers are no longer native to Scotland and this one was deposited in the Black Isle.
"We are looking closely at similar incidents in Tayside and we believe there are strong links."
The Black Isle beaver's body is being held at a museum in Edinburgh.
Ch Insp Eddington said samples may be taken with the hope of checking its DNA against any obtained from other cases.
The officer said the release of the beaver into an unfamiliar and inappropriate environment was "reckless".
He said: "The cause of death was ingesting large quantities of sea water.
"Beavers need freshwater and the only open water this one found was the sea. Its stomach was found to be full of water, otherwise it was found to have been a healthy animal."
Once native to Britain, beaver were hunted to extinction more than 400 years ago.
However, damaged trees have been recorded in Perthshire, Angus and Fife, and it was thought illegally released animals were to blame.
Last month, the Scottish Government announced the European beaver is to be reintroduced legally to Scotland for the first time in more than 400 years.
Environment Minister Michael Russell has given the go-ahead for up to four beaver families to be released in Knapdale, Argyll, on a trial basis.
The beavers will be caught in Norway and released in Spring 2009.