LONDON — Rupert Murdoch has expressed regret for questioning the competence of police carrying out an investigation into wrongdoing at his U.K. newspapers, but says the probe has gone on too long.

In a secretly taped recording that emerged earlier this month, the media baron called wrongdoing by his British newspapers "next to nothing," boasted that his lawyers were refusing to actively cooperate with investigators, and spoke dismissively about accusations of bribery leveled against his newspaper empire.

He also described police as "totally incompetent" in the recording, obtained by the ExaroNews journalism website and broadcast on Channel 4 News.

The tape prompted an influential Parliamentary committee to recall Murdoch for questioning about media wrongdoing and lawmaker Keith Vaz to write to Murdoch asking him for an explanation.

In a written response to Vaz made public on Thursday, Murdoch conceded he had used the "wrong adjectives" when voicing his frustration with the investigation.

"I am in no position to judge the competence of the investigation and should never have done so," he said in the letter. "My own lay view is that it has been more than thorough, indeed it has in some respects appeared to be excessive."

Murdoch pointed to employees who were arrested in 2012, early in the investigation, and "are still in limbo" awaiting charging decisions from prosecutors.

"This has gone on too long," he said, questioning whether police have approached the investigation "with an appropriate sense of proportion" or with regard to the human costs of delay.

The recording — allegedly made secretly when Murdoch addressed staffers from The Sun newspaper back in March — made waves in Britain because it appeared to be at odds with Murdoch's vigorous public condemnations of illegal behavior at his newspaper titles.

Scotland Yard had previously said it is seeking a copy of the recording with an eye toward "assessing the full contents of that tape."