A TELEPHONE sex pest, who resurfaced a week ago after more than two years of silence, appears to have gone quiet.

But police are urging the public to continue being vigilant, as they make efforts to trace the man who targets teenagers with obscene calls.

About 200 reports have been made to officers from victims in Darlington and the surrounding area in a period of four years.

In 1998 alone, there were 50 calls. But after the beginning of 1999, the caller went quiet until Friday, September 7, when he contacted a Darlington teenager.

In almost every case, the caller has claimed to be representing a radio station and asked to speak to a teenager, never asking by name, for a survey. After a few general questions, the tone of the call becomes of a sexual nature.

The man often asks for details of the victim's friends, often offering incentives such as compact discs in return.

Some of the calls made in 1998 were to youngsters in the Trimdon, Spennymoor and Willington areas.

PC John Milburn, the officer hunting the caller, has said the man might have connections with Oxfordshire.

He has repeatedly claimed to be from Fox Radio, a station operating in that county, but the station has been contacted by detectives and has been ruled out of the inquiry.

Some calls have been made from Darlington Market Place, but many are known to have been made through an Internet exchange and cannot be traced.

PC Milburn said: "We always got the feeling that he was on the Internet. You bounce off exchanges, so you might be using an exchange in America and coming back to Darlington and cannot be traced."

He said: "We would ask people to remain vigilant, especially teenagers, in giving out friends' numbers and personal details."

Anyone with information, or who has received any calls, is asked to contact PC Milburn on (01325) 467681.