An armed burglar in Australia has pleaded guilty to breaking into the home of an elderly woman in 2001 after being caught using evidence from a leech.

The bloodsucking creature was found beside a safe in the Tasmanian home at the time of the incident and a DNA sample matched that of 54-year-old Peter Alec Cannon of Karoola.

Cannon's DNA was taken by the authorities in 2008 when he was being tested for drug offences, The Mercury reports.

Detective Inspector Mick Johnston said: "It was the only evidence we found, and as there was no evidence of any leech bites from the victim or the police present we thought it was a good chance to have come from one of the offenders.

"It is the oddest way of convicting anyone I have ever been involved in. I have not been able to find any similar cases anywhere in the world - nothing like this at all."