Police have arrested a second person over the murder of a pizza delivery driver who was stabbed to death as he delivered his last order.
Thavisha Lakindu Peiris, 25, was found dead in his car on Sunday night in the Southey area of Sheffield.
A 25-year-old man and a 17-year-old boy are both in custody after being arrested separately on suspicion of murder.
Mr Peiris was on his last shift before starting his dream job when he died in what police described as an apparently random attack.
His family described him as the "most caring and loving son a parent could have".
Speaking from their family home in Sri Lanka, his father Sarath Mahinda Peiris and mother Sudarma Narangoda said: "We sent our son to the UK to study so he can have a better life. Now we are left with only a broken heart.
"We were devastated and shocked to hear of our son's tragic end and we are still unable to comprehend that he is actually gone.
"Thavisha was one of the most caring and loving sons a parent could have. He was full of life and always had a smile on his face. Anyone who met him immediately liked him.
"He was a deeply religious boy who would not even harm an ant."
"We urge anyone who knows anything about our son's tragic death to come forward to help bring whoever is responsible to justice. Please help the police stop another father or mother feel the tragic loss that we are feeling."
Mr Peiris's older brother Pramod Chetheka Peiris said: "I am heartbroken. My brother Thavisha was the centre of our world.
"He gave us so many reasons to smile. He was kind and considerate and we were extremely proud of his achievements.
"We were so happy that he was doing so well in England. We never thought his life was in any danger.
"I can't believe he was taken away from us in this cruel and inhuman manner.
"Please, if anyone saw or heard anything that could help us catch these murderers, we beg that you step forward to help find my brother's killers."
Mr Peiris was found slumped in a silver Toyota Yaris car in Southey Crescent, in Sheffield, at about 10.30pm on Sunday.
He was found by fellow Domino's workers who had gone looking for him after he failed to deliver his last ever order.
Mr Peiris came to the UK to finish an IT degree and graduated from Sheffield Hallam University in 2011.
He had just secured a job as an IT consultant in the city.
His colleagues and police said he had been feeling unwell during his last shift and was going to go home early but agreed to deliver one last order.
More than 50 police staff are involved in the investigation and his family are understood to be making plans to travel to South Yorkshire.
The officer leading the murder inquiry, Detective Superintendent Lisa Ray, said she did not know why Mr Peiris was killed in an apparently random attack.
She said robbery was a possibility but it appeared no money had been taken.
Domino's Pizza has said it was funding the cost of flying Mr Peiris's family to the UK in the coming days.