GENEVA (DPA) - A 75-year-old woman has been detained as a suspect in Switzerland after a seven-year-old schoolboy was stabbed to death on Thursday (March 21) on a street in Basel, a prosecution spokesman said.

The boy was on his way home after school when he was attacked with a knife, spokesman Peter Gill told the local Basler Zeitung newspaper.

A teacher from his school found him on the pavement and immediately called an ambulance, but he died in hospital despite emergency surgery.

"There was information that an elderly person was at the scene, and soon afterwards, a 75-year-old Swiss woman turned herself in to the prosecution authority," Mr Gill said. "She said she had stabbed the seven-year-old to death."

"So far, we have no idea what the motive might have been," he added, calling on people who might have further information to come forward.