LONDON — The taint of Britain’s phone hacking scandal was creeping closer to media baron Rupert Murdoch today as journalists dissected a trove of correspondence which appeared to cast doubt on denials given by some of his most trusted lieutenants.

New documents published by U.K. lawmakers investigating the scandal apparently contradict claims made by the News Corp. chief’s former right-hand man and challenge testimony delivered to Parliament by his son James Murdoch.

Among them is a letter claiming that illegal espionage was pervasive at Murdoch’s now-defunct News of the World tabloid.

Former Murdoch confidante Les Hinton said in 2009 that he’d seen no evidence that phone hacking had spread beyond a single rogue reporter at the tabloid. Yet Hinton is among those copied in on the explosive letter.

Three former executives are also challenging assertions by James Murdoch that he wasn’t told the full facts about the scandal.

But even as the pressure mounts on Murdoch’s entourage, others caught up in the scandal may be able to breathe a little easier.

The Independent Police Complaints Commission, Britain’s law enforcement watchdog, announced today that it was dropping its investigation into four former top police officials, including former Metropolitan Police Commissioner Paul Stephenson.

Stephenson resigned amid allegations that police didn’t properly investigate the wrongdoing at the News of the World because of their close ties to the Murdoch empire – accusations that have shaken Britain’s most important police force at a time of budget cuts and rising social unrest.

Misconduct probes into John Yates and Andy Hayman, both former assistant commissioners, were also dropped, as was an investigation into Peter Clarke, a former deputy assistant commissioner, the police watchdog said.

The watchdog’s deputy chair, Deborah Glass, said that while revelations about senior police officers’ close ties with Murdoch executives – including meetings, lunches and dinners with people who’ve since been arrested – had had an impact on public confidence in the force, her organization had to identify “what is, and what is not, conduct that needs to be investigated.”