Pulitzer Prize-winning journalist Seymour Hersh recounts in his new memoir a rumour he heard about Richard Nixon beating his wife, Pat.

On August 9, 1974, Nixon left the White House in disgrace and retreated with his wife to their seaside estate in San Clemente, California.

A few weeks later, Hersh says he was contacted by a source at a nearby hospital who said the former first lady had been treated at the facility for injuries inflicted by her husband, the Daily Mail reports.

"I was called by someone connected to a nearby hospital in California and told that Nixon's wife, Pat, had been treated in the emergency room there a few days after she and Nixon had returned from Washington.

"She told doctors that her husband had hit her. I can say that the person who talked to me had very precise information on the extent of her injuries and the anger of the emergency room physician who treated her," Hersh recalls in his new memoir, Reporter.

Hersh, who was working in the Washington, DC bureau of the New York Times at the time, said he dug into the story further - reaching out to Nixon's former domestic affairs advisor, John Ehrlichman, to see what he thought of the rumour.

"I called him and told him, with more specifics than I am writing here, about what had happened to Pat Nixon in San Clemente. Ehrlichman stunned me by saying that he knew of two previous incidents when Nixon struck his wife.

"The first time was in the days after he lost the race for governor of California in 1962, when he bitterly told the press that it was his last political race and they would not have 'Richard Nixon to kick around anymore'.

"A second assault took place during Nixon's years in the White House," Hersh, who famously uncovered the My Lai massacre, recalled.

Despite getting confirmation from at least one Nixon confidante, Hersh said he decided not to write the story at the time, or even tell any of his editors.

Hersh says he explained his reasoning for not writing the story while giving a talk to journalism fellows at Harvard's Nieman Foundation in 1998.

"The issue was the merging of private life and public life, and I explained that I would have written about the attacks if they were an example of why his personal life impinges on policy, but there was no evidence of such a link.

"I added that it was not a case where Nixon had gone looking for his wife with an intent to hit her, could not find her, and bombed Cambodia instead," Hersh explained.

The reaction he got from the students made him reconsider his actions.

"I was taken aback by the anger my decision generated among some of the female fellows, who noted that battery is a crime in many jurisdictions and wondered why I did not choose to report a crime. "What if it's another crime that he's committing?" I was asked. "What if he went in and robbed a bank?"

"All I could say was that at the time I did not - in my ignorance - view the incident as a crime.

"My reply was not satisfactory. I did not comprehend then, as the women who challenged me did, that what Nixon had done was a criminal act.

"I should have reported what I knew at the time or, if my doing so would have compromised a source, have made sure that someone else did," he writes.

This isn't the first time that similar stories have been told about Nixon. Journalist Anthony Summers said in his 2000 book The Arrogance of Power: The Secret World of Richard Nixonthat he had heard of at least "three alleged wife-beating incidents" from his sources, including former Nixon campaign aide John P. Sears and Pat Hillings, a longtime friend and associate of Nixon.

At the time that book was published in 2000, Nixon's daughter Julie Nixon Eisenhower issued a statement through her father's library, vehemently denying the allegations.

When reached by DailyMail.com on Thursday, the Richard Nixon Foundation again dismissed the allegations as an attempt by Hersh to sell books.

"The salacious charges in a new book regarding the personal relationship between President and Mrs Nixon, who were married for 53 years, were denied forcefully and emphatically by the Nixon family when they appeared in another book eighteen years ago. They are nothing more than cheap gossip and implausible hearsay, from anonymous or biased sources, repackaged to attract publicity and sell books," the statement read.

By all other accounts, the Nixons were a perfect couple. The two met in the late 1970s, when they were both in their mid-20s, acting in a play in Whittier, California. At the time, Pat was teaching high school and Richard was a recent Duke Law grad trying to set up a practice.

On their first date, Richard asked Pat to marry him and she thought 'he was nuts or something!'

They continued to court for two years, with Richard even driving Pat to and from her dates with other suitors. They finally married in 1940.

While Pat said in interviews that she wouldn't have chosen the life of a politician's wife for herself, she stood by her husband through each of his many campaigns.

The couple had two daughters, Tricia and Julie, who are now ages 72 and 69.

Pat Nixon died from lung cancer at the age of 81 in 1993. Her husband died less than a year later, after suffering a stroke, also at 81.