Chilling CCTV footage shows a masked man suspected by police in the brutal execution of a drug dealer at his home.
Images of the unknown man were released in the hunt for the killer who blasted Redwan El-Ghaidouni, 38, as he sat in his car at his Uxbridge home.
Police believe the father of three was assassinated, soon after he had been released from prison for smuggling drugs.
The masked man fled the scene on foot via an alleyway, sparking a manhunt.
El-Ghaidouni's wife Samantha Taitt said her husband "never stood a chance" against the gunman.
"I was expecting my beloved Redwan to return home from work to look after our three children. As he arrived home he was executed and he never stood a chance.
"Our three young children will now grow up without their loving father. His mother, father and siblings are left without a son and brother.
"We would like to appeal to the public to assist the police with any information they can provide.
"We are left numb with pain and he will be greatly missed."
Detective Chief Inspector Noel McHugh said he believes "several people" know the identity of the gunman and appealed for them to come forward.
"We do believe this was a targeted attack and part of our enquiries are focused on Mr El-Ghaidouni's past," he said.
"He was linked to criminality and had recently served a sentence for drug importation. Did someone have a grievance against him related to drugs or other criminality?
"This was a brutal murder which was clearly well-planned and I'm sure there are several people out there who know why Mr El-Ghaidouni was killed. Please approach us in confidence."