Murphy, 32, was pronounced dead Sunday at the hospital. An autopsy has been completed, but a determination of the cause of death will await the results of toxicology tests in a few weeks. Officials say early indications suggest no foul play was involved.
"My world was destroyed yesterday," husband Simon Monjack, who was in the house at the time she was stricken and who watched as paramedics tried in vain to revive her, told Access Hollywood on Monday afternoon.
It was Murphy's mother who found her unresponsive, he says. When Murphy didn't come out of the bathroom after a long time, her mother checked on her – then screamed for Monjack, who dialed 911, he says.
Up until then, it had been a "regular day" for Murphy except that she had been tired lately from work and what had seemed to be a minor case of laryngitis, Monjack says.
Murphy's half-brother Jeff Bertolotti, meanwhile, expressed anger at the death of his sister, whom he hadn't seen since 2001 after "the Hollywood walls went up" and the closest he could get to her was a phone call to a manager that wasn't returned.
"People come into the town with their dreams and get chewed up alive and those who make it get chewed up alive anyway. And that's what happened to Brittany," he tells PEOPLE. "She's a casualty of that town."
Although acknowledging he knows "nothing" about her husband and others around her in recent years, Bertolotti says, "I'm not saying it's their fault, but I do think they should have taken care of her better. I think she should have been cared for.
"Look, if she died at 32, something is not right," he adds. "What happened? I don't get it. At 32 years old something happened. I don't know what. I'm sure there was no foul play. It's just that something is wrong. ... It's heartbreaking. I was crazy about that kid."