POLICE investigating the murder of a North-East businessman in Central America believe he may have known his killer.

The body of Thomas Purvis, a 44-year-old security expert, was found by a friend in Costa Rica on Monday. He had 11 stab wounds in his back.

Police said there were no signs of forced entry in his second-floor apartment in the fashionable Sabana Sur district of the capital San Jose.

They suspect Mr Purvis, from County Durham, may have let his killer into the building.

Mr Purvis, who moved to Costa Rica in 2002, is thought to have been killed over the weekend. He was last seen parking his car at 9am on Saturday, but could not be contacted over the weekend.

A friend finally persuaded the owner of the building to enter the apartment at 10am on Monday, when he was found dead.

Mr Purvis was believed to have been involved in selling microchips that can be implanted under the skin as a security measure.

He had been living at the address where he was found for the past nine months and is not thought to have relatives in the area.

Investigators said there were no signs of robbery at the secure building and that his sports utility vehicle was in its parking space on the ground floor.

Police spokesman Franciso Ruiz said: "It is possible that the cause of death was revenge because there are no indications of robbery."

British Embassy official Vicky Baxter-Amade identified the body at the scene. She said: "At this stage, we are still waiting for more details from the police investigation."

A Foreign Office spokesman said Mr Purvis' next-of-kin had been informed.

He declined to say where in County Durham Mr Purvis was from.

He said: "Officials are providing appropriate consular assistance."

Mr Purvis is the fourth visitor to Costa Rica to be have been murdered in the past three years.