The gunman did not say anything but aimed his gun at Jama and fired. A bullet whizzed past his left ear, Jama said.
"He started killing people one by one."
Terrified, Jama ran for his life and hid.
He saw others fleeing over fences and high walls.
He saw the gunman's car parked outside the mosque, with the boot open.
Inside, there were other guns, along with two jerrycans of petrol.
The gunman coolly returned to the car on several occasions to grab a new weapon before re-entering the mosque to resume his slaughter.
"He was not afraid," said Jama, ex-president of the mosque, adding that he never ran. He took his time.
After the gunman fled – racing across town to then attack and kill another nine people at Linwood Mosque – Jama found a bloody scene at his place of prayer.
There were dead bodies and wounded worshippers lying on the ground. One woman had been executed with a bullet to the head, he said.
One man passed him with a dying 3-year-old child.
He has been left in a state of shock by the massacres.
"We are all very sad. We are a small community. We are here in New Zealand, especially in Christchurch, we are very safe.
"Christchurch is number one in the world for safety and security. We are shocked. All Muslims are now shocked."
