Nottinghamshire officers believe the Bulwell man may have shot Marian Bates during a now infamous raid on her jewellery store in Arnold in September 2003.

Detectives also suspect Brodie could have since been murdered and divers and sniffer dog teams were used to search for his body in and around a deep quarry pool opposite Watermead Country Park.

About a dozen officers and archaeologists were at the site, which belongs to a gravel and fishing pond business just off the A46.

Det Chief Supt Neil James, leading the search, said: "There is a small stretch of water and we have police divers searching, it's a possible site where James Brodie may, and I must stress, may, have been abandoned.

"This investigation has been going on for some considerable time and we are consistently analysing, evaluating and responding to various pieces of information and this is just one example of that."

Peter Williams (22) of no fixed address, was arrested and found guilty of Mrs Bates' murder in March 2005. Although he was one of the robbers, police have never found the man who actually pulled the trigger.

Brodie was 20 when he disappeared shortly after the robbery and police continue to search for him, dead or alive.

To coincide with the search, Brodie's younger brother, Stephen (18) is making an appeal for information.

He said: "We are under no illusions. It's more likely he is dead. Four years is a long time to be missing. If he's out there I want justice to be brought. If he's not alive, I want justice to be brought for him.

"There's a family out there still grieving and they deserve justice and if he has done this, he should be serving a long sentence. But if he's dead, he needs a family funeral."

The area searched on Tuesday belongs to Wanlip Sand and Gravel and includes two pools, one filled with water and another with quick sand.

Two divers spent about two hours in the murky water in the morning as other officers scoured the surrounding land.

Det Chief Supt James added: "There will be ongoing assessments of how the search is going on but we're not in any particular rush. If we don't discover anything here we've got a number of lines of enquiry, this is just one of them."

Police are still offering a £10,000 reward for information leading to James Brodie's arrest and conviction, or the discovery of his body.

Anyone with information can phone the Nottinghamshire Police incident room on (0115) 844 6994 or Crimestoppers, which is free and anonymous, on 0800 555 111.