Who is Kyrsten Sinema? Former US Senator accused of seducing member of security team, breaking up his marriage

Former US Senator Kyrsten Sinema allegedly had a romantic relationship with a member of her security team, which, according to his ex-wife, led to breaking up of the man’s marriage. Heather Ammel is seeking at least $75,000 from Sinema in a lawsuit. She further accused her of seducing him, according to New York Times.

Matthew and Heather Ammel had “a good and loving marriage” with “genuine love and affection” before Sinema became involved, Heather Ammel claims in her legal filing, asserting that Sinema pursued Matthew despite knowing he was married.

The lawsuit states that the Arizona lawmaker’s head of security hired Matthew Ammel after his retirement from the Army in 2022, and that he travelled with Sinema to locations including Napa Valley, California; Las Vegas; and Saudi Arabia, according to AP.

In early 2024, Ammel’s wife discovered “romantic and lascivious" messages he had exchanged with Sinema via the Signal messaging app. That summer, he stopped wearing his wedding ring, and Sinema gave him a position as a national security fellow in her Senate office while he continued serving as a bodyguard for her campaign, the lawsuit alleges.

The lawsuit also claims that Sinema paid for psychedelic treatment for Ammel, who has faced challenges with post-traumatic stress, substance abuse, and traumatic brain injuries linked to his military service in Afghanistan and the Middle East.

Sinema and her attorney did not respond to AP's requests for comment.

The lawsuit was quietly filed late last year in Moore County, North Carolina, and drew worldwide attention this week after being transferred to federal court.

Sinema’s parents separated during her childhood, after which her mother, who had custody, remarried. Sinema later moved with her mother, stepfather and siblings to DeFuniak Springs, a small town in Florida’s Panhandle.

She won the 2018 Senate race to succeed retiring Senator Jeff Flake, defeating Republican candidate Martha McSally. As an independent, Sinema was one of four non–party-affiliated senators, along with Bernie Sanders, Angus King and Joe Manchin, all of whom caucused with the Democrats. She emerged as a crucial swing vote during the closely divided 117th and 118th Congresses.

Sinema announced she would not run for reelection on March 5, 2024, and was later succeeded by Democrat Ruben Gallego.

In January 2025, Sinema joined Coinbase’s Global Advisory Council, where she took on a role advocating for the cryptocurrency sector and helping the company engage with US lawmakers.

Two months later, in March 2025, she became a senior advisor at the law and lobbying firm Hogan Lovells.

Sinema unsuccessfully sought to lobby the city council of a Phoenix-area suburb to approve the development of an AI data center in October 2025, during which she disclosed her alignment with the Trump administration’s approach to building AI infrastructure. Earlier that year, she had founded the AI Infrastructure Coalition and assumed the role of its co-chair.