Ana Walshe’s romantic entanglement with William Fastow took center stage during Brian Walshe’s murder trial on Thursday. Fastow, who described their relationship as “intimate,” revealed that their affair commenced prior to Ana’s mysterious disappearance on January 1, 2023.

As a realtor, Fastow played a pivotal role in helping Ana secure housing in Washington, D.C. This location was convenient for her commute from the family residence in Boston to her workplace. Fastow, sharing similar family dynamics, testified about his own separation from his wife and the children they had together.

While leaving an open house in the Spring Valley area of Washington, D.C., Fastow recounted the details of his affair with Ana. They connected deeply over mutual interests, such as fitness, and the shared challenges of parenting, which eventually led to their romantic involvement.

During his testimony, Fastow noted that although he never spent the night at Ana’s Washington townhouse, she would occasionally stay at his place. He claimed the affair wasn’t a tightly held secret, yet Ana had expressed a desire for her husband to hear about it directly from her, should he ever learn of it.

They became close, bonding over common interests, including in fitness and over the struggles they had in common as parents. Then they began their affair, he said.

Although he never stayed at her Washington townhouse overnight, she stayed at his, he said. He said he did not keep the affair a secret generally, but that Ana had told him that if her husband ever found out, she wanted him to find out from her.

Brian Walshe arrives at Norfolk Superior Court in Dedham, MA, Monday, December 1, 2025. Walshe is facing murder charges for the death of his wife, Ana Walshe. (David McGlynn for Fox News Digital)

Still, the two went on a trip to Dublin, Ireland, for Thanksgiving in the months before her murder. After Dublin, Ana flew to Serbia to visit her mother, while he returned to Washington.

“Ana was extremely disappointed that she wasn’t in a position to be the mother she believed the children deserved,” Fastow testified.

Ana Walshe wears a Washington Capitals jersey in a December 2022 post. (Ana Walshe/Instagram)

He testified that Ana told him that her children lived with their father in Cohasset, a suburb of Boston, because Walshe’s home confinement for a federal art fraud conviction was contingent on him being their primary caretaker.

Prosecutors have alleged two potential motives in the slaying. The first is anger over the affair. The second is because he allegedly believed he would have a better chance of avoiding federal prison if his wife were out of the picture and he was the only caretaker for their three children.

Walshe’s defense has denied that he had any knowledge of the affair, although he mentioned Fastow more than once during interviews with detectives before his arrest and allegedly looked him up on the internet before Ana’s disappearance.

Her remains have not been found, but prosecutors showed the jury Wednesday a saw and hatchet recovered from a dumpster near Walshe’s mother’s house that the defendant allegedly used to dismember his wife. The same dumpster also had her COVID-19 vaccination card, clothes, bloody towels and a cut-up rug suspiciously similar to one taken from the family home.