A young apprentice plumber text his mother to tell her he was being held captive in the Lindt cafe in Sydney.
His mother, Mel, said she received a text at 3pm that read: "Mum, I'm in the Lindt cafe in Sydney."
"My heart stopped, I sent back a text message: 'What is going on? Are you OK?," the frantic mother told 2GB radio station.
"I'm OK Mum, can't talk," he replied.
Mel - who cannot be fully identified to protect the identity of her son - told presenter Ray Hadley that this was the last communication she has had with her son.
Radley has been reportedly speaking with a number of hostages from inside the cafe throughout the day.
He has claimed he has refused to put one of the calls live on air, despite instructions from the sole gunman.
An unknown number of hostages have been taken inside the café and five have escaped so far, at least five hours after the siege started.