This method, normally used in rape cases, reflects the sexual nature of the attacks, which have caused widespread alarm and outrage locally. Concern is growing as the attacks have spread from Hampshire to Buckinghamshire.
The latest attack took place last weekend when a mare had part of its foot hacked away and a blunt instrument inserted into its vagina on a farm near Princes Risborough, only a few hundred yards from the scene of an identical incident three weeks ago.
PC Bill Slater, head of the Hampshire Horsewatch network, said that feelings are running high. 'We have to proceed with caution. Any named suspect could be the victim of a lynch mob.' He is also worried by the sudden increase in attacks. 'In 1991 we had two, in 1992 we had 18; this month we've already had four.'
Police in Buckinghamshire said yesterday: 'We are following two good lines of inquiry.'