David Cameron has vowed the police will do "everything possible" to catch and punish the killers of Anuj Bidve, as he spoke to the murdered Indian student's parents on Friday.
The prime minister telephoned Bidve's father Subhash to express sympathy after his 23-year-old son was shot dead in the street on Boxing Day, to express his sympathy.
Bidve's parents are in Britain and visited the spot where their son was killed on Friday. Police closed streets around the crime scene as his mother, Yogini and father Subhash laid flowers during their emotional visit.
A Number 10 spokesman said: "The Prime Minister spoke to Subhash Bidve, the father of Anuj Bidve, this afternoon by telephone.
"He expressed his sympathy on behalf of the whole country for this terrible murder.
"He assured Mr Bidve that the police and the British justice system would do everything possible to ensure that the perpetrators were caught and punished and he wished his family a safe return to India."
Earlier on Friday, the PM expressed "huge sympathy" for Bidve's family, saying his life had been "cruelly and brutally ended".
"My message, on behalf of the whole country, is one of huge sympathy and understanding to them."