Eyewitnesses say that Jordan Begley was unarmed and being pinned to the floor by police officers when he was shot by a 50,000-volt stun gun.
“They could have arrested him on the doorstep and they had him on the floor, but instead they shot him,” one witness told the Manchester Evening News.
“He didn’t have a knife at any point and we just couldn’t believe what was going on.”
Jordan had a heart condition but the Home Office post-mortem failed to establish the cause of his death.
His family is set to launch legal action against Greater Manchester Police.