07/09/2011 10:36 BST | Updated 07/11/2011 10:12 GMT

Steven Grisales, 21, Stabbed To Death After Asking Youths To Stop Throwing Conkers

PRESS ASSOCIATION -- A young man was killed after he remonstrated with a group of youths for throwing conkers at him, police have revealed.

Steven Grisales, 21, protested when his assailants launched their missiles as he walked towards a London railway station last month.

But moments later he was knifed in the chest. He died of his wounds in hospital the next day.

A post-mortem examination following the attack, near Silver Street station in Edmonton, north London, gave his cause of death as a single stab wound to the heart.

Just weeks before he was attacked, on August 31, Mr Grisales had returned to London from Argentina where he had moved to live with his father. He had been hoping to start a three-year architectural course this month as part of a scholarship from Westminster College.

Detectives believe he was set upon by up to three young black males, possibly in their late teens or early 20s.

A Scotland Yard spokesman said: "Officers now believe the incident began after conkers were thrown at the victim as he made his way towards Silver Street railway station. He initially remonstrated with the youths but one of the suspects produced a knife and stabbed him."

Mr Grisales, of Enfield, north London, was rushed to the Royal London Hospital following the attack on College Close shortly after 7pm.

Four people have now been arrested in connection with his murder. Two 15-year-old boys were held on Monday and remain in custody at a north London police station.

A 19-year-old man and a 16-year-old girl arrested on Friday have been bailed until next month.