Two children were killed alongside their mother in a horror car smash moments after two separate cars were seen apparently racing nearby.Sanjay and Pawanveer Singh, aged 10 years and 23 months old, were passengers in a BMW car with their mother, when they were caught up in what one witness described as a “massive” multi-vehicle smash.Three cars, also including a Bentley and an Audi S3, were involved in the collision on the Birmingham New Road at the junction with Lawnswood Avenue in Wolverhampton at 8.45pm on Thursday, West Midlands Police said.The driver of the Bentley car, a 31-year-old man, has been arrested on suspicion of causing death by dangerous driving. He has been released pending further investigation. The Audi driver has not been traced.A picture of Sanjay happily holding his younger brother in front of a Christmas tree was released by police alongside a tribute from their family. They said: “Our family are grieving over the tragic deaths of our two beautiful children, as well as dealing with the shock of the horrific crash. “We appeal to the general public to come forward as witnesses in order help police find the perpetrator who fled from the scene and to bring him or her to justice. Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. “It was too much. The mother was just in shock.”Eyewitness Dudley Hartley said police quickly cleared the area and moved onlookers away – after immediately realising the severity of the children’s injuries.Mr Hartley, who went outside to see if he could help at the scene, said: “It was absolutely shocking. To see something of this nature and then to discover there were two fatalities, both children, is shocking.”Accident investigators were on the scene overnight, where the blue Audi could be seen with a crumpled front end. “At this time we would appreciate some privacy and space to grieve over our precious loss. “Your co-operation in this would be very much appreciated.”Witnesses claim the driver appeared distressed after being accused of racing with the Audi, which struck the family car at traffic lights on a dual carriageway.Police are attempting to find the Audi driver, who left on foot.Passersby rushed to the scene in an attempt to help the victims and comfort and treat their mother.A spokesman for West Midlands Ambulance Service said: “Unfortunately, it soon became apparent that nothing could be done to save the two young boys who had been badly hurt and they were confirmed dead at the scene.”The mother was taken to hospital seriously injured.A taxi driver told reporters two cars had passed him at a “very, very fast” speed about a mile away from the accident scene.Describing how two cars had passed him at speed, Tanveer Hussain added: “I was further up the road, by McDonald’s, and two cars overtook me. If I am doing 35 to 40, they were doing much more.”Explaining what happened after he heard a bang and then saw the crash site, Mr Hussain added: “I got out of my car and other lads tended to the children. What I saw was terrible.