08/13/2014 03:23 EDT | Updated 10/12/2014 05:59 EDT

Robin Williams's Family Speaks Out Following Actor's Death

The family of legendary actor and comedian Robin Williams remembered the Oscar winner on Tuesday. 

Williams's three adult children expressed a deep love for their father, who was found hanged in his California home Monday, and disbelief upon hearing the news he had taken his own life. 

"I'll never, ever understand how he could be loved so deeply and not find it in his heart to stay," said his 25-year-old daughter Zelda. 

"He was always warm, even in his darkest moments," she noted, adding she last saw her father when he recently celebrated his 63rd birthday. It was a day, Zelda recalled, that she and her two brothers spent "sharing gifts and laughter" with their father.

"Dad was, is and always will be one of the kindest, most generous, gentlest souls I’ve ever known, and while there are few things I know for certain right now, one of them is that not just my world, but the entire world is forever a little darker, less colorful and less full of laughter in his absence," Zelda wrote in a statement issued Tuesday. 

In an emotional post just two weeks before his death, the actor sent a heartwarming message to Zelda for her 25th birthday that included an old snapshot of the pair in happier times.

In the accompanying caption, Williams wrote, "Happy Birthday to Ms. Zelda Rae Williams! Quarter of a century old today but always my baby girl."

'My heart is split wide open'

Williams's eldest son from his first of three marriages, Zachary Pym “Zak” Williams, 31, said he lost "a best friend and the got a little grayer."

"I will carry his heart with me every day. I would ask those that loved him to remember him by being as gentle, kind, and generous as he would be. Seek to bring joy to the world as he sought," Zak wrote. 

Marin County Sheriff's Lt. Keith Boyd said Williams was last seen alive by his wife, Susan Schneider, who went to bed around 10 p.m. Sunday. She awoke the next morning and left the couple's Tiburon home, thinking he was asleep somewhere else in the house.

Williams's second wife Marsha Garces, the mother of Zelda and Cody Alan Williams, 22, released a statement of her own Tuesday, saying "my arms are wrapped around our children as we attempt to grapple with celebrating the man we love, while dealing with this immeasurable loss."

"My heart is split wide open and scattered over the planet with all of you. Please remember the gentle, loving, generous – and yes, brilliant and funny – man that was Robin Williams," Garces wrote. 

Cody, who is himself an assistant director working in Hollywood, said Tuesday, "I will miss him and take him with me everywhere I go for the rest of my life, and will look forward, forever, to the moment when I get to see him again."  

Lt. Boyd confirmed that the actor, who had been open about his struggles with addiction, was being treated for depression at the time of his death.

Toxicology tests are being conducted to determine if Williams was under the influence of drugs or alcohol at the time. Results won’t be available for two to six weeks.

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