Murder squad detectives are investigating the death of a pensioner who was beaten up in his car.

George Osborne was punched and his head smashed against the steering wheel by a young male pedestrian.

Mr Osborne, who was in his mid-seventies and lived in north Brighton, drove away after telling passers-by who came to his aid that he was fine.

Minutes later his red Ford Fiesta crashed into a telegraph pole in The Crestway, Brighton.

Steve Knight, owner of Your Stores in Hollingbury Place, was working in the shop and saw what happened at about 6pm yesterday.

He said: "The old guy was coming round the corner of Roedale Road in his car when this young bloke in a yellow jacket walked out in front of him.

"He was acting a bit flash, as though he was determined the old man would stop for him."

The old man pulled up in front of the shop and Mr Knight said he heard him say something to the man in the yellow jacket.

Mr Knight added: "The young bloke seemed to go mental and must have been off his head because he walked over to the car and started punching the old bloke and smashing his head against the steering wheel.

"The bloke was nuts. I have never seen anything like it. He didn't seem to want to stop."

Mr Knight said he thought the attacker was in his twenties and about 5ft 2in tall.

Members of the public tried to stop the attack.

Mr Knight said: "He got out of the car to make a call. I went over with a box of tissues because he was bleeding. I asked him if he was okay and he said, 'I'm fine'."

The man got back into his car, did a U-turn and drove away towards The Crestway, where his car crashed.

A Home Office pathologist was today conducting a post-mortem examination to determine whether Mr Osborne died from natural causes or from injuries suffered in the assault or crash.

Detective Chief Inspector Sally Simmonds, heading Operation Nucleus, said: "We are treating the death as suspicious but we are keeping an open mind as to the cause.

"This was a tragic death and our sympathies go to Mr Osborne's family.

"We now need to establish exactly what happened, and we urgently need to speak to witnesses."

PCs Daniel Sweitlik and Ben Wallis, who were investigating a nearby burglary at the time, were first at the scene and tried to resuscitate Mr Osborne.

He was pronounced dead on arrival at the Royal Sussex County Hospital, Brighton.

Gary Walters, of Good Taste Cafe, said the ferocity of the attack had shocked local people.

He said: "This is a small community and nothing like this has ever happened here before."

Peter Berry, a cleaner at Linfield Court, near the crash scene, said: "The road was cordoned off for hours. Residents saw police cars and ambulances there, and lots of flashing lights but no one seems to know exactly what happened."

Frances Harrison, of Roedale Road, said her son was attacked last September just metres from last night's attack.

She said: "It is getting quite worrying because it used to be such a nice area. I have lived here 30 years and it has changed quite a lot."

Philip Philippou, of J and E Fish Bar, said traders had been pressing for CCTV cameras because of a rise in crime during the last year.

He said: "It is hard to believe a young man did that to an older person."