A beaver that was released in to the wild as part of the Scottish Beaver Trial earlier this year may have been shot just days later.

The adult female vanished just a week after its family was released in to the wild in North Knapdale in Mid-Argyll on May 29.

The disappearance coincided with gunshots heard in the area by staff working on the trial, which aims to reintroduce the native species more than 400 years after they were hunted to extinction in the 16th century.

Strathclyde Police are investigating the unauthorised shooting, which took place on Forestry Commission land.

Scottish Beaver Trial (SBT) staff have also launched a search for the rest of her family, a male and young female, which they believe were scared away.

The family, one of three released in the project, had been recorded feeding, swimming and playing together in Loch Chreag Mhor for a week, before the gunshots were heard in early June.  

SBT field officer Jenny Holden said she was walking with her partner when they heard rifle shots close to the site.

She said: "When we returned to look for the beavers the next evening, only one beaver was seen in the loch."

She added: "We don't know whether she has been shot or whether she has been frightened.

"It is very unusual circumstances for a beaver, especially a female, to go away from the young."

The male was later sighted on the Crinan Canal but has not reappeared, while the juvenile also left Loch Chreag Mhor in search of its parents.

SBT staff have been unable to locate either animal. They are using radio tracking equipment to locate the beaver but have still not found it.

The juvenile is still missing, although it is believed to be following the scent of its parent.

Two other families of beavers which were released in Loch Coille Bharr and Loch Linne were not disturbed and are continuing to attract wildlife watchers.

Allan Bantick, Chair of SBT, said: "We are thrilled that two families of beavers have settled into their new surroundings so quickly.

"I very much hope that the missing female from the third family has not been shot and await the result of the police investigation."

The release of the beavers at carefully selected sites was the first formal reintroduction of a native mammal species into the wild in the UK.

The beavers, originally from Norway, were chosen because they are considered to be the closest type to those once found in the UK.