LONDON — James Murdoch will be recalled for a second grilling before Britain’s Parliament, a senior lawmaker investigating the tabloid phone hacking scandal said today.

The announcement from John Whittingdale, the chairman of Parliament’s media committee, comes after former Murdoch executives raised serious doubts about the credibility of the dramatic testimony given by James and his father Rupert, head of the News Corp. media empire.

A string of ex-News Corp. employees have cast doubt on several claims made by the father-and-son media magnates on July 19.

Specifically, former News of the World tabloid editor Colin Myler and former legal adviser Tom Crone insisted that James Murdoch was wrong when he claimed not to have been made aware of a critical piece of evidence suggesting that illegal espionage was far more widespread at the tabloid then was being claimed.

James Murdoch has stood by his testimony. A spokeswoman for News Corp., which the younger Murdoch serves as deputy chief operating officer, said that he was “happy to appear in front of the select committee to answer any further questions members might have.”

Alice Macandrew said that the company would “await details of the committee’s request.”

Whittingdale told Sky News television that his committee was “beginning to reach the end of its deliberations” but wanted to tie up “one or two loose ends” by recalling witnesses. He said he also wanted to quiz former Les Hinton, Rupert Murdoch’s former right-hand man, and Mark Lewis, a lawyer for many people who have sued the tabloid for hacking into their phones.

Whittingdale didn’t give a specific date for the new testimony. Neither Hinton nor Lewis immediately returned messages seeking comment. Hinton, the former publisher of Murdoch’s U.S. flagship, The Wall Street Journal, is the most senior executive to resign in the hacking scandal.

In a separate development, a lawyer said in a British High Court that the mother of a July 7, 2005 London transit bombing victim was among those suing the News of the World over allegations of illegal espionage.

Hugh Tomlinson says Sheila Henry, whose son Christian Small was killed in the 2005 suicide bombings, was among those seeking damages from the now-defunct British paper.

It wasn’t immediately clear Tuesday whether Henry believed that she or her son had been spied upon in the News of the World’s efforts to obtain scoops.