A massive manhunt continues for a gunman after the murder of a criminal lawyer in Bankstown on Tuesday afternoon.

The victim, Ho Ledinh, was at the Happy Cup cafe at Bankstown City Plaza when he was shot dead at point-blank range at about 3.40pm.

Hours after his "best friend" was gunned down, 59-year-old Van Nguyen remained at the scene showing bystanders photos of Mr Ledinh happy and smiling.

Mr Nguyen said Mr Ledinh - a criminal lawyer, originally from Vietnam who once owned the Bankstown cafe where he was shot, was a great man.