It was seven years ago when Peter Cannon along with his accomplice targeted an isolated property in Northen Tasmania in Australia and robbed 71 year old Fay Olsen after tying her up.Their faces hidden under black hoods, and clutching pieces of wood, they forced their way into the victim’s home.

The robbers opened the safe, took $500 (equivalent to £200 at the time) and found another $50 in the elderly woman’s handbag. They then tied up and a belt tightened around her ankles.
They fled before Miss Olson could free herself and when police arrived they were unable to find any obvious clues.

But one vigilant police officer found something which did not belong there a blood sucking leech totally satiated with blood and since Fay Olsen did not have any marks with leech bites, he took the leech to the lab , rightly concluding that the blood in the leech belonged to one of the thieves.

The creature was examined and the DNA extracted from the blood. All police needed then was a person to match it with.
It was seven years before Cannon was arrested and charged with drug offences - and when his DNA was compared with that taken from the leech a match was found.

Crown prosecutor John Ransom told a judge in Tasmania that the chances of the DNA from the leech matching someone else were one in a 100million.

Cannon, 54, pleaded guilty to aggravated armed robbery committed in 2001 and will be sentenced on Friday. The police is still searching for his accomplice. Forensic Detective Science is surely going places.