A pizza delivery driver was delivering his last ever order before starting his dream job as an IT consultant when he was stabbed to death, his boss has said.
Thavisha Lakindu Peiris, 25, was found slumped at the wheel of his car on Sunday evening in the Southey area of Sheffield.
His manager at the nearby branch of Domino's Pizza, Ravi Marripudi, said Mr Peiris has not been feeling well that evening and he had agreed to make one last delivery before going home.
Mr Marripudi said he set off to take the pizza to Southey Crescent - about a mile from his base - at about 9.50pm.
But 15 minutes later he got a call from the customer saying the order had not been delivered and there were voices outside.
The manager said he sent another driver to look for Mr Peiris and he found his colleague unconscious in his Toyota Yaris, in a residents' parking bay near the delivery address.
"It is so shocking," Mr Marripudi said.
"He was such a kind person.
"If someone had wanted money, he would not have fought. He would have handed it over.
"He was just a really nice person."
Mr Marripudi said the incident had worried delivery drivers and four have decided to quit since the murder.
"He wasn't feeling very well and he wanted to go home but he said he would deliver this last one," he said.
Mr Peiris came to the UK from Sri Lanka to study IT at Sheffield Hallam University.
He graduated in 2011 and had started working at Domino's to help fund his studies.
Mr Marripudi said: "He was very excited about his new job."
A 50-strong police team is now working on the murder inquiry.
The police officer leading the investigation, Detective Superintendant Lisa Ray, said her team did not know why Mr Peiris had been killed.
She said she could not rule out any motive, including robbery, although she said a small amount of cash was still with him in the car, which did not have Domino's livery.
The detective said a "career-minded, hard-working, bright, articulate and friendly young man" suffered a "brutal and shocking death".
She said: "Thavisha Lakindu Peiris was a bright, hard-working, intelligent and caring man who had worked hard to develop his career in Sheffield.
"His murder is an absolute tragedy and has caused untold grief for his mother, father and brother in Sri Lanka and for his many friends in Sri Lanka and in Sheffield.
"Everything we have learned from his family, friends and workmates at Domino's suggests he was a career-minded, hard-working, bright, articulate and friendly young man who was very much planning his future. To date, we have found no explanation for his brutal and shocking death.
"I need to hear from anyone who knows anything about his murder."
Mr Peiris's family are preparing to travel to South Yorkshire, police said.
The attack happened in a parking bay reserved for residents of the quiet street, which is just a short distance from a busy roundabout on one of the main routes across the north of Sheffield.
Speaking at the scene, Ms Ray said it was dark and raining on Sunday night.
The detective said that although the silver Toyota was not marked as a Domino's vehicle, Mr Peiris was wearing one of the firm's T-shirts. But she did not think any money was missing.
She said the vehicle was being forensically examined, although this was a slow process due to the rain on the night.
Ms Ray said Mr Peiris suffered stab wounds to his chest and it was not entirely clear where he was when he was attacked. He was found sitting in the driver's seat with both doors closed. But, the detective said, he could have been attacked as he was standing in the doorway of the vehicle.
"I can only imagine the pain that his family in Sri Lanka are feeling, hearing this news," Ms Ray said.
"He was very close to his family. He spoke to his mother every single day that he was in the UK.
"I'm appealing now to the mothers that are out there.
"Is it your son that came home a little bit dishevelled, perhaps with blood-stained clothing?
"I'm asking for anybody out there to think about that family and the end of that young life at the age of 25."
She said a number of people had been arrested following the death but all had now been eliminated from the inquiry and released without charge.
Ms Ray said Mr Peiris had no family in the UK apart from a cousin in London. He is understood to have lived with other Sri Lankan people in an area of Sheffield near the Northern General Hospital, about a mile from where he died.
No-one was available to talk at Mr Peiris's home in the Fir Vale area of Sheffield.
His neighbours said they knew him as a pleasant, quiet man.
"I used to see him walking past and say hello," said Jawad Iqbal.
"He was a really nice, humble person."
A spokesman for Sheffield Hallam University said Mr Peiris graduated in 2011.
He said: "The university is saddened to hear of the tragic death on Sunday of Thavisha Peiris, who successfully graduated in 2011 with a degree in information technology.
"We encourage anyone with information to contact South Yorkshire Police."
Later, at Mr Peiris's home, his house mate and fellow IT worker Hassan Natheer vowed to continue his friend's dream.
Mr Natheer said Mr Peiris loved his delivery job but wanted to pursue his IT career.
"He was a kind person," he said. "He just worked hard."
Mr Natheer said: "He was ready for the next step in life. He just wanted to finish off with Domino's. He loved the job but he wanted to come back again to IT."
He said: "We've lost him forever now. I think we should keep up all his dreams."
Mr Natheer said his friend was really looking forward to his new job and enjoyed being part of the Sri Lankan community in Sheffield.