Katherine Hartley Short was reportedly found dead behind a locked bedroom door with a suicide note and a gun nearby

Sources have also now told TMZ homicide investigators reportedly responded to a call at her home in the Hollywood Hills, California, and ruled out foul play.

She is said to have been found with a self-inflicted gunshot wound.

A representative for Martin confirmed her death in a statement to Page Six on Tuesday (24.02.26.)

They said: "It is with profound grief that we confirm the passing of Katherine Hartley Short.

"The Short family is devastated by this loss, and asks for privacy at this time. Katherine was beloved by all and will be remembered for the light and joy she brought into the world."

A neighbour told Us Weekly Katherine had not shown visible signs of distress before her passing.

They added: "Katherine was a private person but that doesn't mean she wasn't friendly. She was quite outgoing."

The neighbour also said they would "hear and see her laughing with friends" on her front porch at times.

Katherine, a psychiatric social worker, had previously written about living with mental illness.

On her now-deleted professional website, she wrote: "Joni is my incredible service dog, who has been assisting me with my own struggles with mental illness for the past 5 years."

She owned the service dog, named after the singer Joni Mitchell, in the years prior to her death.

In 2012, Katherine legally changed her surname from Short to Hartley.

In documents explaining the change, she wrote: "My father is a public figure and I am a psychiatric social worker."

She added: "I am worried about potential harassment from future patients resulting from my association with my father."

Katherine maintained a low public profile and was last seen publicly celebrating her 40th birthday in 2023.

Martin, known for his role in Only Murders in the Building, adopted Katherine with his late wife Nancy Dolman.

The couple also adopted sons Oliver Patrick, 39, and Henry Hayter, 36.