A landowner has said Animal Liberation Front (ALF) activists who let his herd of red deer escape committed a "gross act of stupidity".
The deer were released by the ALF in May
When the animals broke out from their Wiltshire home in May, it was thought fence-removing vandals let them out.
But now a notice has appeared on an ALF website claiming responsibility.
Michael Petley of the Potterne Deer sanctuary said: "What has escaped them is that this is a sanctuary for deer, not a breeding house for meat."
The ALF struck at the sanctuary on 25 May, releasing more than 20 red deer.
Their website says: "We had to leave a group of baby deer imprisoned at the farm because they were too young to fend for themselves.
"We will return, and these deer will be saved from certain death. We will not let these innocent animals end up on the dinner table. This is just the beginning."
But Mr Petley pointed out they had targeted a sanctuary rather than a farm and had threatened to come back for baby deer which were actually a herd of mature fallow deer.
"This is a gross act of stupidity and unkindness to these animals.
"It saddens me enormously to see our Deer Sanctuary at Potterne subject to such extensive and malicious damage," he said.
Mr Petley, a fund manager who works in London, said: "If it was done with the mistaken intent of liberating these animals the reality is they have done anything but.
"This was a herd that was living happily and securely. They were watered and fed and now they are in unknown territory in which they are not suited or used to."