Deutsche Telekom has asked the public prosecutor in Bonn to investigate allegations that its security staff misused call data records on a number of occasions in order to track contacts between board members and journalists, according to company sources.

The misused records, of who called whom, when and for how long, relate to calls that took place in 2005 and 2006, according to the sources.

Such records are routinely kept by telecommunications operators about all their clients, as they are essential to the billing process, but details of the calls made on a particular line are usually only made available to the bill payer.

Hewlett-Packard hit the headlines in 2006 when it admitted that investigators working for the company had obtained the call data records of nine journalists without their permission, part of an operation at the company to plug boardroom leaks. In that case, the investigators contacted telecommunications providers pretending to be the journalists in order to obtain their records, a process that became known as pretexting.

Deutsche Telekom first became aware that call records had been misused in the middle of last year, after an internal tip-off. An internal investigation lead to changes in procedure and a reorganization of the security team, the company said Saturday.

However, Deutsche Telekom said that on April 28 it received a letter containing renewed and more serious allegations from someone outside the company claiming to have been involved in the incidents at the request of a member of the company's security department.

After studying those allegations, the company filed charges with the public prosecutor's office on May 14. Staff at the public prosecutor's office were aware of the dossier, but would not comment further.

"We ... will support them in their full investigation of these allegations," CEO Rene Obermann said in a prepared statement.

"By taking this approach we want to ensure the greatest possible level of transparency and allow criminal prosecutors to bring those responsible to justice," he said.

The HP pretexting case ultimately cost Chairman Patricia Dunn her job, but Deutsche Telekom's senior executives should be safe.

"We are talking about incidents in 2005 and 2006 which were under the jurisdiction of the former management team," said company spokesman Mark Nierwetberg.

Obermann was named head of Deutsche Telekom in November 2006, having previously led its mobile subsidiary T-Mobile. Chairman of the board Ulrich Lehner was only appointed on April 17, just before the current round of allegations broke.