Nearly 40 years after a schoolboy was stabbed to death in southern England, two men have been arrested in connection with the crime, police said Tuesday. Police also want to speak to an English family that emigrated to Canada soon after the murder.

Keith Lyon, a 12-year-old boy from the southern coastal city of Brighton, England, left home to buy a geometry set on a Saturday afternoon in May 1967 and never returned.

He was found clad in his school uniform on a grass bank near a rural bridle path between the nearby villages of Ovingdean and Woodingdean, about 56 miles south of London. He had been stabbed 11 times in the chest, back and abdomen with a serrated kitchen knife.

The case caused shock across Britain and police in both Sussex, a county in southern England, and at London's Scotland Yard launched one of the area's largest ever investigations, taking more than 5,000 fingerprints from youths.

Witnesses claimed there had been a scuffle between an older group of schoolboys and Lyon, but no arrests were made at the time. Police theorized that Lyon, a student at the posh Brighton and Hove Grammar school, was targeted by local youths because of his uniform.

Two men, a 55-year-old man from Manchester, 200 miles north of London, and a 56-year-old man from Brighton, 54 miles south of London, were arrested last Thursday.

Both have been released on police bail to return for additional questioning on Nov.14, police said in a statement on Tuesday. Neither man has been charged with any offense.

Investigators hope to trace a family that emigrated to Canada shortly Lyon was found dead, Heard said.

She said the family, who police have not named, left the country abruptly after the murder and at the time had a teenage son.

The unlikely breakthrough in the case began four years ago, when a crew of workmen stumbled upon a locked storeroom at a Brighton police station and found key evidence, including the murder weapon, which had previously been misplaced, said Sue Heard, a Sussex police spokeswoman.

She said DNA testing of the murder weapon had led to the arrests.

"I have had to live my life with not knowing why my brother died for 39 years, but knowing that the person or persons who murdered him is living their life without being punished," Keith's brother Peter Lyons said in a statement.

He said their parents had both died without seeing someone brought to justice for the killing.

Detective Inspector Tim Nunn, leading the investigation, said he hoped that people may come forward who have previously refused to disclose vital information.

"I believe there are people who know who committed this murder but have not had the confidence to speak to the police about it. Now is the time to do so, so that Keith's remaining family can finally understand what happened," Nunn said.