FBI probe London teacher who drugged more than 90 boys with sleeping tablets before molesting them

The FBI are investigating the London links of a serial paedophile who admitted molesting at least 90 young boys during his 40-year career as a teacher.

William Vahey, 64, killed himself in March after being exposed as a child molester by a colleague at a school in Minnesota.

The school employee found a hard drive filled with "pornographic images of minor males who appeared to be asleep or unconscious".

It is believed the victims are around 12 to 14 years-old.

When confronted, Vahey admitted he had molested boys his whole life while on school trips after giving them sleeping pills, the FBI said.

Abuse: Vahey worked in at least nine international schools during his 40-year teaching career

The bureau is now attempting to identify possible victims of Vahey who is known to have worked at American international schools in at least nine different countries including Southbank International School in London.

Southbank's chair of governors, the former chief inspector of schools, Sir Chris Woodhead, said the school was "deeply, deeply shocked" by the revelations.

Sir Woodhead said Vahey had taught boys aged 11 to 16 and been involved in school trips.

He told the Guardian parents are showing "considerable concern" and is planning to hold a meeting or write to parents in the next 24 hours.

Vahey was jailed in California in 1969 for child molestation, but Woodhead said that nothing showed up on criminal record checks or references taken in the UK.

At the time of his suicide, Vahey was married with two adult children. He had homes in London and on Hilton Head Island, South Carolina.

The FBI said: "While the review is ongoing, the FBI is seeking to notify individuals of the existence of the investigation and encourage additional potential victims to come forward."