"He went with a whimper and not a bang and it was very emotional ... We had experts in the room and tried to let him know this was a disease. It was a tough and very emotional day and the last thing he said before he left was, 'I want to get better.' And I believed him."
Murphy insists he was satisfied Monteith was making good progress until several weeks ago when the actor and his girlfriend Lea Michele came to visit him while working on a TV movie in Fire Island, New York.
He says he asked Monteith if he was having problems again.
"I honestly couldn't tell what was going on with him. He didn't seem quite himself, but when I confronted him he claimed he was clean."
Murphy goes on to praise Michele for her bravery as she dealt with her devastating loss.
"It has been a very difficult rollercoaster ride, and all through that, and through the last week, Lea has been the most brave and courageous person I've ever met.
"She has dealt with an impossible situation with more humanity than you could ever hope for."
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- WENN