Jerry Oppenheimer is a New York Times bestselling author whose latest book is The Kardashians: An American Drama. He has also published best-selling biographies of Hillary Clinton and Robert Kennedy.

Wearing a green jacket that read 'I really do care,' Ethel Kennedy celebrated at the annual Hyannis Port annual Fourth of July parade.with a clear slap at the first lady.

Just a week before, it was announced that the 90-year-old would be participating in a hunger strike to protest President Trump's immigration policies on the southern border.

But Ethel's protestations may be somewhat hypocritical, as Robert F. Kennedy's widow ‘treated her immigrant servants like dogs,’ according to insiders who worked for her.

After RFK's assassination in June 1968, Ethel was the sole mistress of Hickory Hill, the Kennedys' fabled estate in McLean, Virginia. became known as 'Horror Hill' because of Ethel's temper tantrums and abusive treatment of the help.

She earned a reputation for slapping and berating immigrant household workers, cheating them out of money, and screaming at them like a 'mad woman,' causing them to flee in tears, or be fired,' sources recalled.

Sympathetic friends blamed her behavior on the depression and anger brought on by the tragic loss of her husband, father of their 11 children, with the last born after he was killed.

Still, she made it a living hell for her help.

'I really don't think Ethel liked Hispanics or blacks,' her one-time secretary, Noelle Fell, told me for my biography, The Other Mrs. Kennedy: Ethel Skakel Kennedy, an American Drama of Power, Privilege, and Politics.

Ethel Kennedy was seen wearing a green jacket that said 'I really do care' while participating in the annual Hyannis Port Fourth of July parade. She is taking part in a hunger strike to protest President Trump's immigration policies on the southern border

Strength in numbers: A number of the family's friends also wore the jackets as they marched in the parade on Wednesday

Insiders who worked for Ethel Kennedy called the hunger strike 'hypocritical' because Robert F. Kennedy's widow 'treated her immigrant servants like dogs. Ethel is pictured above with Robert Kennedy and six of their children outside their home in McLean, Virginia, in March 1958

Fell, one of a number of Ethel's former employees interviewed for the book, asserted that Ethel 'couldn't stand it if [the immigrant help] didn't speak English well, or understand it. Ethel would say something once, and if they didn't understand it she would be furious, scream at them and threaten to fire them, or worse.'

But now, in her golden years, as one of the last of the renowned Kennedy wives, she has volunteered to fast for 24 hours as part of a 24-day hunger strike, in memory of the more than 2,000 immigrant children from south of the border who have reportedly been separated from their parents while illegally crossing from Mexico into the U.S.

As part of the protest, the Kennedy widow was to make a financial donation in lieu of the food she would have eaten, according to her daughter, Kerry Kennedy, who heads the Robert F. Kennedy Human Rights organization, a nonprofit advocacy group.

'We want to find a way for people who can't go down to the border to actually do something themselves at home that is concrete and creates change, and this is what we're calling on them to do,' said Kerry, Ethel's seventh-born child.

She described her mother as 'very joyful' about the protest -#BreakBreadNotFamilies.'

But immigrants from south of the border who were employed by Mrs. Kennedy in the years following her husband's murder found 'no joy' in working for her, sources stated.

As one asserted, 'They were treated like dogs.'

And even an African American woman in her employ suffered verbal racial abuse, recalled Kennedy brother-in-law, actor Peter Lawford.

Ethel Kennedy is pictured at the table eating with Kennedy children during the celebration of the christening of Christopher George Kennedy, Hyannis Port, Massachusetts, in July 1963. One of the family's maids looks on as the children and their mother eat at the table

One woman who worked for the Kennedys who got under Ethel's skin was skin after RFK's death was the senator's favorite among the help – Ena Bernard, a black woman from Costa Rica. Bernard is pictured above with some of the Kennedy Children. The photo features a note written by RFK, reading: 'To Ena, Who has kept them looking up all this time'

Sitting in the kitchen at Hickory Hill nursing a cup of coffee, he later claimed, he witnessed Ethel voicing a racial slur at a maid who was cleaning, and inadvertently tossed an item that Ethel was saving, involving her late husband.

As Lawford later recounted, 'Ethel screeched, "What are you doing?"

'The maid said, "I'm throwing this away, Mrs. Kennedy."

'And Ethel said,"'You stupid ******. Don't you know what you're doing? Get out of my sight. You're fired!" The woman fled in shock.'

Returning to his home in Los Angeles, Lawford mentioned the scene to his then wife, Patricia Seaton Lawford, who recalled, 'Peter was very upset. He had been very much into the civil rights movement and he hated what Ethel had said.'

'Over the years he had seen a lot of self-righteous behavior in Ethel.'

Noelle Fell, however, noting that she had never heard Ethel use the N-word, remembered 'she would say things like, "black people are stupid."

To members of the Kennedy circle, Ethel's use of a racial slur seemed incomprehensible because she and her late husband – renowned in the civil rights movement – were friends with the likes of such celebrated African Americans as Coretta King, widow of Dr. Martin Luther King; the Olympian Rafer Johnson, and Cesar Chavez, the Mexican-American labor leader and civil rights activist.

Ethel's son, Robert Kennedy Jr., would later claim that his mother never used such racist language.

But Ethel could also be physically abusive – especially to South American immigrants with poor language skills - as underscored by an incident witnessed by Fell.

'Ethel had asked one of the maids, who had difficulty with English, to bring her a jar of face cream,' recalled Fell.

Attorney General Robert F Kennedy eats breakfast with his family in Mclean, Virginia, in June 1964 as one of the family's maids, believed to be Ena Bernard, helps the children

And when RFK was murdered, Ena, who had a room on the third floor at Hickory Hill, was heartbroken. Ena is pictured above watching Bobby Kennedy play with two of his children

Ena Bernard, pictured far left with Ethel and her children, started working for the Kennedys them in the early 50s when then-congressman and future president John F. Kennedy secured a green card for her, using the influence of his congressional office

'When Mrs. Kennedy asked for something it had to be right away. When she was in a hurry everything flew.'

The servant somehow misunderstood what she had been told and soon returned with sanitary napkins, rather than the requested face cream.

Furious, the Kennedy widow 'hit her in the face, just slapped her,' Fell told me.

The maid 'was crying and she ran to the basement and said she was going to leave. I said, "Mrs. Kennedy's not in a good mood today."

But, according to Fell, the maid said, 'I'm never going to work here again. No one has ever slapped me.'

Fell confronted Ethel. 'I said she's a very good worker. I don't feel we can lose her.'

The maid stayed on. A few weeks later she suffered a minor injury at Hickory Hill, and with guests present, Ethel made a big to-do over her, announcing she would personally drive her to a nearby hospital.

As Fell saw it, 'Mrs. Kennedy was a great actress. She was trying to show her guests what a nice boss she was. I remember her saying – and I laughed to myself when I heard it – "I have really valuable people working for me. She's one of the best."

'But if Mrs. Kennedy didn't have an audience – watch out!'

Kennedy brother-in-law, actor Peter Lawford (second from right with Eunice Shriver, left, Ethel Kennedy, second from left, and Joan Kennedy, right) claimed an African-American woman working for Ethel suffered verbal racial abuse

Future employees, including those with black or brown skin, were warned about working for the Kennedy widow at her five-acre estate, located across the Potomac River from Washington, D.C., long since sold.

'When you go out to Hickory Hill, if you don't like her, and she doesn't like you, you're going to know it,' said an insider.

'If that happens, for God's sake, do not take the job. Working for Ethel can be totally and utterly lethal.'

One who got under her skin after RFK's death was the senator's favorite among the help – Ena Bernard, a black woman from Costa Rica.

'If it wasn't for Ena,' the presidential hopeful was known to say, 'this place [Hickory Hill] would fall apart.'

He considered her the Kennedy family's 'treasure.'

She had begun working for them in the early 50s when then-congressman and future president John F. Kennedy secured a green card for her, using the influence of his congressional office.

His brother, Bobby, who was attorney general in the Kennedy administration, later arranged for Ena to accompany President Kennedy on an Alliance for Progress trip to her homeland, where she was accorded a virtual hero's welcome.

Later, Bobby Kennedy arranged to bring Ena's daughter, Josefina, to the U.S. from the Bernards' hometown of Heredia, Costa Rica.

And when RFK was murdered, Ena, who had a room on the third floor at Hickory Hill, was heartbroken.

But Ethel, so possessive of RFK, had come to loathe Ena, and wanted to fire her, apparently always jealous of her close friendship with RFK, and her control of the raucous Kennedy household.

Richard Burke, who had worked as Sen. Ted Kennedy's personal assistant, was aware of the war between Ethel and the Costa Rican servant.

Motivated matriarch: Ethel Kennedy wore a green jacket that said 'I really do care' while participating in the annual Hyannis Port Fourth of July parade (Ethel above with son Max and his wife Victoria)

Ethel has volunteered to fast for 24 hours as part of a 24-day hunger strike, in memory of the more than 2,000 immigrant children from south of the border who have reportedly been separated from their parents while illegally crossing from Mexico into the U.S. Pictured above, a family who had been reunited in Miami after fleeing violence in Guatemala and crossing the Mexico border into the United States

'Ena really called the shots' at Hickory Hill,' he said.

'She was the one everybody always went to, nobody went to Ethel. I never saw the kids running up to their mother. They always went to Ena first. The older kids shied away from Ethel, avoiding her like the plague.'

When Bobby was alive, Ethel had smiled and tolerated Ena. But that changed after his death.

As one Kennedy insider noted, 'Mrs. Kennedy wanted to get rid of her so bad.'

This ignited fights between Ethel and her older children, Kathleen and Joe, who had adored the heavyset woman since they were toddlers - the woman their mother had come to despise.

As Ethel's sister-in-law Patricia Kennedy Lawford noted, 'Everyone who wondered how Ethel could raise eleven children knew when they saw Ena in action.'

As one RFK son, Christopher, remembered Ena, 'She would praise us in English and get mad at us in Spanish.'

But Ethel always berated her often in harsh English.

'Mrs. Kennedy would get ticked off at Ena and yell, "Get out! I don't need you here!"

Another insider noted, 'Ethel felt Ena was a thorn in her side because Ena knew too much about the family, that she was a snoop who always had her ear to the door.'

When asked why she took Ethel's abuse, Ena claimed she stayed because of the Kennedy children.

But when Ethel had one of her tantrums, or did something to embarrass herself, Ena gloated, according to Noelle Fell.

She recalls Ena once confiding, 'The thing I miss most about the senator is that he used to put Ethel in her place. He would take her by the shoulders, sit her down, and give her a talking to…You know the reason why Mrs. Kennedy had so many children? Because that was her way to make sure her marriage stayed together.'

Ena 'Mimi' Bernard, who spent more than four decades with the Kennedys, managed to endure Ethel's abuse, until she retired, dying at the age of 105 in July 2013.

At the door of her little home in Sunrise, Florida, was a Kennedy family memento – a ceramic Dalmatian, a gift from the one Kennedy woman who wanted to fire her – Ethel Skakel Kennedy.