Two US senators have turned up the heat on Les Hinton, the former chief executive of Dow Jones who resigned last week, calling on the panel that oversees the company's editorial integrity to investigate his role in the scandal.

Barbara Boxer of California and John Rockefeller of West Virginia have written to the special committee of Dow Jones and company demanding that they set up an inquiry into whether senior Dow Jones executives, Hinton especially, had any knowledge or role of alleged criminal activity at News Corporation.

They wrote: "Allegations of illegal phone hacking and bribery in the UK at properties owned by News Corporation, a US-based company, have outraged people around the world. The American people need to be reassured that this kind of misconduct has not occurred in the US and that senior executives at News Corporation properties in our country were not aware of, or complicit in, any wrongdoing."

The special committee of Dow Jones was set up at the time of the company's sale to Rupert Murdoch in 2007 in order to assuage fears that the media tycoon would affect its journalistic integrity. The committee was tasked with ensuring the "continued journalistic and editorial integrity and independence of Dow Jones' publications and services."

Dow Jones is the publisher of the Wall Street Journal, the most prized possession within Murdoch's newspaper holdings.

Hinton resigned as head of Dow Jones last Friday, becoming the most senior member of Murdoch's inner circle to fall foul of the billowing phone-hacking scandal. He was chairman of News International, the UK newspaper arm, at a time that illegality took place, though he has denied any knowledge of it.

He twice told parliament that the hacking was limited to one News of the World reporter, a claim that is now known to be a gross underestimate.

The two senators, who have already pressed the US justice department to launch an investigation into News Corporation activities within America, asked the special committee whether they raised any concerns about Hinton's appointment as head of Dow Jones in 2007, and whether or not they investigated the extent of his knowledge of illegality at News International.

The senators' intervention is the latest move to increase pressure on News Corporation on the US side of the Atlantic. An FBI investigation is underway into allegations that NoW reporters tried to gain access to the phone records of 9/11 victims and the justice department has launched a preliminary investigation into whether Murdoch companies broke any other US laws.