Police revealed today that two shots were fired at the Hells Angel biker shot dead on the M40, as his grieving girlfriend said he “left a void in so many lives that can never be filled”.

Gerry Tobin, 35, was killed with by single bullet to the back of the head as he drove home from the Bulldog Bash, a motorbike convention, in the Midlands on Sunday afternoon.

At the motorbike shop where the dead man worked Marcus Berriman, president of the London chapter of the Hells Angels, read a statement on behalf of Tobin’s girlfriend Rebecca Smith, condemning the “callous and cowardly act of violence” that ended the British-Canadian’s life.

“To those who knew him, Gerry stood out in the crowd as a true gentleman. He was a rare breed of man with the heart of a lion and a soul filled with compassion and selflessness,” he said.

“He was Rebecca’s soul mate and she feels truly blessed to have spent five wonderful years of her life, the best five years, with such a wonderful man. She will always miss him.”

Detective Superintendent Ken Lawrence, who is leading the investigation, revealed new information about the crime, saying that the police now thought two shots had been fired at Tobin as he sped along the motorway near Stratford-Upon-Avon.

He had driven about 30 miles from the Bulldog Bash when he was attacked, heading home to his partner in southeast London, when a dark green or blue Rover sped out from a lay-by and tracked him down. Police believe that a passenger fired the fatal shot.

The car is thought to have raced from the side of the motorway and overtaken two Polish bikers, who were driving with Tobin, before it was close enough to shoot the Canadian man.

The shot was fired by a handgun, most likely from the front passenger seat of the Rover 620. It is unclear whether there was also a third passenger in the backseat of the car, but police are searching for the vehicle and anyone who saw it on Sunday.

Officers believe that a number of anonymous tip-offs have given them "significant information" as they attempt to solve the murder case.

The detective admitted that it was still unclear why anybody would have wanted to kill Tobin, who had a reputation for being friendly and helpful despite his membership of the notorious motorcycle gang.

He said he would be “astonished” if he had been murdered by a fellow Hell’s Angel because of their famed loyalty, which left other biker gangs as the most likely culprits.

“There is a distinct possibility that it was a rival gang,” Detective Superintendent Lawrence said. “It is possible that he was targeted for something he had done or he could have been targeted simply for being a Hell’s Angel.”

His membership of the gang would have been apparent to anyone that saw him riding his Harley Davidson back to London – his bike and his leather jacket were emblazoned with the Angel’s insignia.

Tobin was born in Macclesfield, but emigrated to Canada at an early age. He moved back to the UK at least ten years ago.

The M40 was closed until Monday afternoon while police scoured the scene for clues. They are now examining CCTV footage that may have captured the incident.

Members of the public have made more than 200 calls with information. However, the police are continuing to appeal for more help from bikers, most of whom have remained reticent. Detective Superintendent Lawrence said: “It would be wrong if I said that the Hell’s Angels group were being completely open and honest with us.”

The Warwickshire force have ordered 10,000 beer mats to be distributed to biker bars and motorcycle festivals across the country. They hope that by appealing to individuals within the biker community someone may come forward with further evidence.

The police are also re-examining a six-year-old case with remarkable similarities. On the same stretch of road in 2001, somebody shot a Canadian as he rode home from the Bulldog Bash. He was wounded in the leg but recovered from the injuries. The gunman was never found.

Times Recommends

• Postman Pat moved to a high-tech sorting office
• Saatchi’s old favourites
• New teaching style gives pupils wake-up call