The brick was thrown from a footbridge

Michael Little, 53, suffered heart failure after he was hit by the brick while driving on the M3 on the Surrey/Berkshire border last month.

Surrey Police are contacting specifically-selected men in the Camberley area to take DNA swabs from them.

The force says it has forensic evidence from the scene, but will not reveal what it is.

Mr Little, who was from Hornchurch in Essex and drove for Ford, was hit by the brick at about 0030 GMT on Friday 21 March, on the northbound carriageway of the M3 near Camberley.

Praise for reaction

Police believe the brick was thrown from a footbridge over the motorway.

Mr Little earned praise from officers for his reaction to the incident, controlling his 44 ton lorry and pulling it onto the hard shoulder to avoid the danger of more accidents.

Surrey Police, who are treating the death as a murder case, have appealed for local people to contact them if they saw anyone behaving suspiciously on the bridge, which is used as a short cut from Camberley town centre to Frimley.

Management at Ford in Dagenham, where Mr Little had worked for 26 years have offered a �25,000 reward for information leading to the conviction of the killer.