Police say the brick was thrown from a footbridge at 0030 GMT
Police have renewed their appeal for help to find the killer of a lorry driver who died when a brick was thrown through his windscreen.
Michael Little, 53, suffered heart failure after he was hit by a brick when driving northbound on the M3 near Camberley on the Surrey-Berkshire border.
Surrey Police said investigative work on his 44-ton lorry had now allowed them to pinpoint the time of the incident.
Officers believe the brick was thrown from a footbridge over the motorway at about 0030 GMT on Friday, 21 March.
Detective Chief Inspector Graham Hill, senior investigating officer for Surrey Police, said he hoped the new details would jog people's memories.
He said: "We know that this footbridge is a popular shortcut home used by people from Camberley town centre back to Frimley.
"We are urging people to think back two weeks ago - did you see anyone hanging around the footbridge at that time?
"Or is there a family friend or relative who has appeared unusually out of sorts since that date?
Family 'devastated by loss'
"We really need you to call us to help solve this murder for Mr Little's family, who are devastated by his loss."
Management at Ford in Dagenham, where Mr Little had worked for 26 years, have offered a £25,000 reward for information leading to his killer.
The father-of-one, who lived in Hornchurch in Essex, managed to pull his lorry onto the hard shoulder, but died from his injuries.
A post-mortem examination showed he suffered heart failure after a blow to the chest.
Surrey Police, who are treating the death as murder, praised his actions in controlling the vehicle, saying it prevented further accidents and calling him "professional to the end".