Although detectives say significant progress has been made, no arrests have yet taken place and police are still keen to talk to anyone who can help.
A £50,000 reward still remains on offer for information leading to the arrest and prosecution of the person or people responsible for Redwan's murder.
Redwan was fatally shot as he sat in the driver's seat of his car on the driveway of the home he shared with his partner and three young children just before 7pm on Tuesday, February 3 last year.
After Redwan pulled into his driveway, he was approached by a man who shot him multiple times through the car window.
The suspect ran off through an alleyway that leads to Saunders Road.
He turned the corner where he was caught on a CCTV camera before running in the direction of Dowding Road.
He was wearing a distinctive dark hooded top with a large logo on the front as well as dark bottoms, dark gloves and dark shoes or trainers.
'Still need to talk to others who may hold vital information'
CCTV also shows the man, again wearing the top with the large motif, in Saunders Road on numerous occasions on Saturday, January 31 and Monday, February 2.
Police believe that these were failed attempts to shoot Redwan.
Detective Chief Inspector Noel McHugh, said: "Extensive enquiries have been carried out over the last year and we have made good inroads into understanding the circumstances surrounding Redwan's murder.
"Our previous appeals have been successful in encouraging people to come forward and I would like to take this opportunity to thank local residents who have been so supportive of our investigation.
"However, we still need to talk to others who may hold vital information.
“I would remind people that a significant amount of money is on offer to anyone who can provide information that leads to the prosecution of those who carried out Redwan's murder."
Police also still want to hear from anyone who can identify a man seen an hour before Redwan was murdered, at about 6pm, standing on the verge by a telegraph pole at the junction of St Andrews Road and Vine Lane, opposite Redwan's house.
'Murder has left three young sons without a father'
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On Monday August 10, 34-year-old Marwais Kakar of Great Field Drive, Uxbridge was sentenced at Isleworth Crown Court to six months' in jail, suspended for two years, for providing false information to detectives investigating Redwan's murder.
DCI McHugh added: "As we've previously said, Redwan did have a criminal past and had been linked to drug importation.
"He had been released from prison almost seven months before his death but he had been working full-time at a car dealership and enjoying being a family man again.
"We continue to look into his background for answers about what happened but whatever the circumstances, his murder has left three young sons without a father and his long-term partner devastated."
Anyone with any information is asked to call the incident room on 020 8785 8099 or Crimestoppers anonymously on 0800 555111 or via crimestoppers-uk.org.