The man who was shot dead on a street in Calgary's northwest community of Arbour Lake was a convicted drug offender with ties to the province's largest-ever ecstasy bust, police say.

Police are on scene of the shooting on Arbour Lake Dr. N.W. that killed a man in his 40s. (Andrew Brown/CBC)

Hui Xu, also known as Phillip Tu, was the 42-year-old brother of Donny Tu, who was shot to death in the doorway of his home five years ago.

At the time, Phillip Tu was serving a three-year jail term for drug offences in connection with the record-setting ecstasy bust, which took place in June 2005.

During the raid, police seized 213,000 tablets of the drug — with an estimated street value of $4.25 million — along with $25,000 in cash, a semi-automatic rifle, body armour, two stun guns and a high-capacity magazine containing 19 rounds of ammunition.

Tu was convicted of drug possession and was sentenced in 2008 to three years in jail with a lifetime firearm ban.

'Died in son's arms'

A blood stain still marks the spot on Arbour Lake Drive N.W. where Tu was shot around 5:40 p.m. on Thursday.

"It was just full of blood there yesterday," said a woman who rushed over to administer first aid to the man as he lay dying.

"He still seemed to be breathing a bit, so I started CPR, but I think he was pretty well gone by that time," said the neighbour, a nurse.

She said she felt sorry for the man's family, especially his son, who was holding his head and trying to stop the bleeding.

"I just feel really sorry for him that he had to watch his father get killed and have him die in his arms," she told CBC News. "That was very sad."

Three police cars were parked outside the house in the 600 block of the busy street on Friday morning.

Jocie Rapini, who has lived in the neighbourhood for 10 years, says there has been trouble at a certain house on the street, with lots of cars coming and going over the years.

"Nice people live here and we can't believe ... something like this happened," she said.

Calgary police are now looking for three suspects — two who were masked, and believed to be men. The gang unit is investigating.

Sgt Colin Chisolm says police are looking for this minivan in connection with arbour lake shooting <a href="https://twitter.com/hashtag/yyc?src=hash">#yyc</a> <a href="https://twitter.com/hashtag/cbc?src=hash">#cbc</a> <a href="http://t.co/xwtIXUuILS">pic.twitter.com/xwtIXUuILS</a> —@Fedun