Police are offering a substantial reward for information they hope will lead them to the killers of a 66-year-old man from Colindale.

Alan Bailey was found dead in his home in Boycroft Avenue on March 3, following a call from neighbours who were concerned he had not been seen for some time.

A reward of £20,000 is being offered for information leading to the arrest and prosecution of the people responsible for the murder.

A police spokesman said Mr Bailey lived most of his life in the area, and was a recluse by nature, known to search restaurant bins for food.

His appearance was described as unkempt.

On November 27 last year, it is thought Mr Bailey was a victim of robbery while he was searching for food behind Pizza Hut in Kingsbury Road between 1am and 3am in the morning.

He then tried to get home, but made it to Lewgars Avenue before collapsing just metres from his house.

He was taken to Northwick Park Hospital and was later discharged.

The spokesman said a post mortem gave cause of death as multiple injuries, and also established he may have been dead for a number of months.

DI Presland, the officer in charge of the murder investigation, said: "Robbery may have been a motive, but given Mr Bailey's unkempt appearance, it is equally possible he was targeted simply for mindless amusement.

"This was a sustained attack on a vulnerable elderly male.

"I would urge anyone who has information to come forward and I hope that this offer of a substantial reward may encourage them to do so."

Two men aged 19 and 20, two 14-year-old boys and a girl, 14, were arrested in connection with the incident on March 26 and 27.

All five were later bailed to return to a north London police station in early July pending further inquiries.

Police still want to hear from anyone who saw Mr Bailey in Lewgars Avenue or the surrounding streets on the night of Monday, November 11, through to the following day.

They are also keen to speak to anyone who may have known him in order to piece together Mr Bailey's movements on that night.

Anyone with information is asked to call the incident room on 020 8358 0200, or to remain anonymous, call Crimestoppers on 0800 555 111.