A CONMAN posing as a policeman tricked his way into the home of a 91-year-old woman - the fifth time the pensioner has been targeted by thieves in three years.

Neighbourhood Watch groups have now been put on red alert after so-called distraction burglars continued their attempts to trick their way into the homes of the vulnerable.

The break-in happened at a house in a quiet road in Eynsham on Monday - and police have linked it with a similar burglary in Enstone, last month when a man posing as a plain clothes detective conned another elderly woman.

Last night, the 91-year-old told how the pretend policeman even opened her front door when she arrived home early from a hospital appointment.

It was the fifth time since 2005 she had fallen prey to distraction burglars.

In the latest incident, the fake officer made off empty-handed - but in previous break-ins, the conmen stole precious jewellery.

She said: "One wanted to test the water and another said he was from the gas people - and now it's someone who said he was working for the police, it really upsets me.

"I'd just come back from Witney Hospital and the door opened in front of me.

"He was already in the house and I found out later he had broken in through the back door.

"Everything was out of the wardrobes and boxes. It was a mess.

"He told me I had been burgled and said he was going to get more police to come and look round.

"Then he mentioned something about boys out the back and said he was going to look."

Her son arrived later and the incident was reported to police who searched the house for fingerprints.

Reinforced bolts have now been fitted to the back door.

The woman's neighbour, Kay Read, said: "It's sick. I've lived here many years and there's been things going on, but this is the worst."

Police are linking the incident to a burglary at a 79-year-old woman's home in The Drive, Enstone, on February 19, where a burglar also claimed to be a policeman.

He forced his way in through a window and, when challenged by the pensioner, said he was investigating local burglaries before making off with gold commemorative coins worth £60.

In both cases, the burglar is described as white, aged in his 30s, thin, with short dark hair. He spoke with a local accent.

Eynsham PCSO Helen Keen said: "These conmen have sank to a new low by posing as police officers to gain the trust of elderly and vulnerable residents.

"We've seen them posing as water board and gas board officials - and now police officers - we are sickened by this."

Penny Thewlis, of Age Concern Oxfordshire, said: "This is one of the vilest crimes you can imagine.

"Unfortunately, elderly people are being targeted because they are vulnerable.

"We run forums across the county to reinforce the community safety message."

Anyone with information on the two incidents is urged to contact police on 08458 505505 or Crimestoppers on 0800 555 111.