The mother of the woman who was killed along with her boyfriend when their car was apparently rammed into the path of another spoke yesterday about the "maniac" who caused the couple's deaths.
Detectives on the case released details about the car used by the alleged road rage driver. The motorists appears to have been incensed because the vehicle in front of him was not going fast enough.
Police believe the driver deliberately slammed into the back of the couple's car three times.
Toby Exley, 22, and Karen Martin, 20, died after their black Ford Fiesta XR2 was finally rammed across the central reservation of the dual carriageway A316 at Hanworth, west London, and into the path of an oncoming Vauxhall Cavalier.
Miss Martin's mother, Kay, said: "There must be someone out there who knows who this maniac is.
"This man is likely to do this again and he needs to be stopped. We want to prevent another family feeling the utter devastation that we're feeling now."
She added: "We're still living a nightmare, we're just hoping that we wake up from it. It's like an absolute void without Karen and Toby.
"They were such lovely people, a beautiful couple. They were very much in love, it was a really serious relationship.
"There is no way that Toby would have taken any chances with Karen in the car as he was too much in love with her to put her in any danger."
The crash took place on Monday of last week but police only released details on Wednesday evening after two witness came forward. The witnesses are believed to have been in vehicles overtaken by the speeding car.
Scotland Yard said the road- rage vehicle is believed to be a "powerful" light-coloured saloon car with a registration number beginning K5.
Investigators believe the couple's Fiesta had just left a 40mph zone at about 8.50pm and was accelerating in the outside lane of the dual carriageway up to 70mph as it neared the M3 and overtook a motorcycle.
But the driver behind became impatient and began bumping into the Fiesta, finally forcing it through a wooden fence on to the London-bound carriageway. The driver of the Cavalier, who suffered a broken arm and teeth in the crash, was still in a state of shock.
Mr Exley, a chef, of Teddington, west London, and Miss Martin, who worked for an advertising agency and lived in Twickenham, became inseparable after starting their relationship in February last year. They were buried next to each other earlier this week.
Mr Exley's brother Robin, 19, said: "The person who did this should be stopped and they should stop and think about our family and Karen's family. Anyone out there could be victims of this person."
If the driver was found, he could face a charge of either manslaughter or causing death by dangerous driving.
Robin also said he hoped his brother's personal organiser could be found as he may have written details about the road-rage car in it., but it is unlikely to have survived the crash.
Anyone with information can contact police on 0181 247 6377 or 0800 555 111.