Author Sir Terry Pratchett has added ten-thousand pounds to a reward to catch the killer of more than thirty swans in Somerset.

Ten more birds were found dead in Wedmore on Tuesday, and the full sum, including donations from members of the public, now stand at over twenty-six thousand.

It was first offered in exchange for information leading to a conviction after eight swans were shot in the head with an air rifle near East Huntspill.

Discworld author Pratchett says he knows the sanctuary where it happened and was 'incensed at the news'.