Martin Short was gripped by fear after going more than a day without hearing from his daughter Katherine — and that desperate concern reportedly led to the tragic discovery no parent ever wants to face.

The beloved comedian and Only Murders in the Building star, 76, called one of Katherine’s close friends after becoming worried about her welfare, according to details cited from the Los Angeles County Medical Examiner’s autopsy report.

Katherine Hartley Short, 42, had reportedly struggled with serious mental health challenges for years. Short’s call prompted her friend to go to Katherine’s home for a wellness check.

What happened next was devastating.

The friend reportedly found multiple notes believed to have been left by Katherine. One note was said to have been posted on the door. The friend then called 911.

When police forced their way inside, Katherine was found lying in her bed. Authorities ruled her death a suicide.

The Short family later confirmed the heartbreaking loss in an emotional statement.

“It is with profound grief that we confirm the passing of Katherine Hartley Short,” the family said.

“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.”

For Martin Short, the loss is another crushing chapter in a life already marked by unimaginable grief.

The comedy legend lost his wife, actress Nancy Dolman, to ovarian cancer in 2010. The couple had adopted three children together: Katherine, Oliver and Henry.

During a deeply emotional appearance on CBS Sunday Morning, Short opened up about Katherine’s long battle with mental illness and spoke about the need to treat mental health with the same seriousness as any other disease.

“The understanding is that mental health and cancer, like my wife’s, are both diseases, and sometimes with diseases they are terminal,” he said.

Short said his daughter had fought for a long time with extreme mental health struggles, including borderline personality disorder.

“She did the best she could until she couldn’t,” he said.

The father of three then drew a heartbreaking connection between the final words of his late wife and what he believes Katherine was trying to communicate.

He recalled Nancy’s last words to him as, “Martin, let me go.”

He said Katherine’s message felt similar: “Dad, let me go.”

Short said he hopes speaking about Katherine’s death can help bring mental health struggles “out of the shadows” and reduce the shame many families still feel when talking about suicide.

The actor has lived through devastating loss since he was young. He lost his father, mother and brother before turning 20, then later lost his wife and now his daughter.

Still, Short said he has come to understand grief as something every person must face in some way.

“The end of life was going to happen to all of us, and for some, it’s too early,” he said.

He added that the best people can do is cherish the time they had with those they loved.

“We have to celebrate and be lucky enough the experiences that we’ve had with them,” he said. “Just to think of them, they’ve just gone into the next room for a while.”

Katherine’s death has left Short’s family shattered, but his decision to speak openly about her struggle has also turned the private tragedy into a public plea for compassion.

For one of Hollywood’s most beloved funny men, the pain behind the smile has never been more heartbreaking.