A young golden eagle may have been illegally killed near Edinburgh and dumped at sea after its satellite tag inexplicably stopped transmitting and then restarted in the North Sea.

The golden eagle was tagged by broadcaster and environmentalist Chris Packham and the campaign group Raptor Persecution UK at a nest in the Scottish Borders last summer, and named Fred, after the landowner’s grandson.

After the eagle fledged from what was the only nest in the region, GPS data from its tag revealed Fred spent several months in his parents’ territory before, this year flying north to the Pentland Hills, “woodland hopping” close to Edinburgh’s bypass.

On 20 January, Fred roosted overnight in trees overlooking a grouse moor. At 10am on 21 January, his tag suddenly stopped working.

On the evening of 24 January, the tag began transmitting again – some 10 miles off the east coast of Scotland beyond St Andrews. The tag continued to provide GPS data until 26 January, showing a final position 15 miles offshore.

Dr Ruth Tingay, of Raptor Persecution UK, said: “It is beyond doubt that Fred’s disappearance is highly suspicious. Golden eagles don’t generally fly out for miles over large bodies of sea water but even if Fred had done so, apart from defying everything we’ve learned about Scottish golden eagle behaviour, we would have seen excellent tracking data plotting his route given the reliability of his tag.

“While we will probably never know for sure, it seems likely that Fred was killed soon after 10am on 21 January, his tag was hidden to suppress the signal and then he and the tag were dumped in the North Sea. If this is indeed the case, it’s just the latest example of when those who have killed a protected bird of prey have tried to cover up evidence of their crime.”

Chris Packham said: “Once again, we have the suspicious disappearance of a satellite-tagged golden eagle in an area managed for driven grouse shooting. What’s truly shocking about this case is that it didn’t take place in a remote Highland glen miles from anywhere, but it happened within a stone’s throw of Edinburgh, right under the noses of the Scottish government.”

A report commissioned by the Scottish government last year found that 41 of 131 satellite-tagged golden eagles had disappeared in suspicious circumstances in Scotland, predominantly on or near to driven grouse moors.

Conservationists accuse some grouse moor managers of allowing the illegal killing of raptors such as eagles and hen harriers because they predate the wild red grouse which are required in large numbers for commercial “driven” shooting.

The Scottish government has ordered a review of grouse moor management with a view to introducing a licensing scheme for game-shooting estates.

A new £1.5m project involving landowners and conservationists will seek to reintroduce golden eagles into southern Scotland this year but Packham said he feared for its success given the ongoing persecution.