The car involved in an alleged hit-and-run crash that killed a husband and wife on a tandem bicycle was being followed by police, it has emerged.
The couple, who died at the scene of the collision in Bristol, have been named as 34-year-old Ross Matthews Simons and 30-year-old Clare Simons.
Friends and family have paid tribute to the couple, describing them as "two peas in a pod" who had just been given the go-ahead to start IVF treatment.
Police investigating the accident revealed the Citroen Picasso involved had collided with the cyclists just moments after officers tried to pull it over.
A statement issued by Avon and Somerset Police said: "Shortly before 4pm yesterday (Sunday), a police officer's attention was drawn to a Citroen Picasso travelling along Lower Hanham Road at speed.
"The officer indicated to the car to stop but it made off. The officer began to follow the car but it was lost to sight almost immediately. Very shortly afterwards the car stuck another vehicle and then collided with two cyclists on a tandem bicycle."
A 38-year-old man is being held by police after being arrested on suspicion of causing death by dangerous driving and the matter has been referred to the Independent Police Complaints Commission.
Police also said a 35-year-old woman had been arrested on suspicion of dangerous driving.
The families of Mr and Mrs Simons released a short statement paying tribute to the couple.
"Both of our families are completely devastated by the tragic events that took Ross and Clare from us," they said.
"A very special couple have been taken from us and we have no words to describe our loss.
"We would all appreciate it if our privacy was respected at this difficult time in order for us to grieve as a family."
Friends of the couple said had been together for several years, married for around 18 months and that they desperately wanted children.
Family friend Diane Pullin, from Kingswood, Bristol, said: "They'd just had news that they were able to have fertility treatment ... everything to live for.
"They were trying for children and they had just been told they could have fertility treatment.
"It's just terrible and it shouldn't have happened. Two young people with their lives in front of them... snapped away just like that."
Inspector Frazer Davey urged any witnesses to come forward.
"Following investigations overnight the circumstances of this collision have become much clearer," he said.
"However, I would appeal to anyone who witnessed this incident or saw this car in the area shortly before the collision to come forward and contact us.
"This is a tragic incident in which two people have needlessly lost their lives. Our thoughts and deepest sympathies are with their families."
Anyone with information is asked to call police on 101 or visit www.avonandsomerset.police.uk