THE police chief leading the hunt for the robbers believes the ‘handsome reward’ will convince criminals to shop their own.

Detective Superintendent Neil Hunter said he hoped the £25,000 put up by the shot security guard’s firm Loomis would provide a breakthrough in the case.

He said: “It's an extremely handsome reward and I hope it will loosen a few tongues in Blackburn and amongst those in the criminal fraternities who, during this credit crunch time, might want to reap the benefits of that amount of money.”

In the days after the incident, police found the bullet during a fingertip search of the scene and forensic tests were carried out for clues.

Then a short time later a dog walker discovered the abandoned cash cassette in a wooded area off Bonsall Street, Mill Hill, near the canal towpath.

This indicated the robbers had used the towpath to escape and hinted they were local.

Police also believe that ink-stained notes stolen in the raid have been in circulation in Mill Hill and other areas of town.

CCTV of the moment the gun was pointed at the guard was released in December in a bid for witnesses to come forward.

But officers need more help from the public, despite yesterday’s arrests.

Mr Hunter said: “We have been working closely with Loomis, who are offering a £25,000 reward to anyone with information that leads to a successful conviction of the offenders.

"This was a heinous crime. Shooting anybody, particularly someone carrying out their job, is a wilful and wicked act."

A security system used by the firm meant that when the cash box was opened a blue/purple ink would have been leaked on to the notes inside.

Mr Hunter said: "Throughout the course of our inquiries it has been suggested that some of the stained notes have been passed around in the Blackburn and Mill Hill area.

“We would like to hear from anyone who has one of these notes, who may have been passed one at some point or anyone who may have been offered them."

Call police on 01254 51212 or Crimestoppers on 0800 555 111.