Bangladeshi police say they have unearthed a mini ordnance factory
Bangladeshi police investigating a huge arms haul in the south of the country are investigating the possible role of the head of a British charity.
The whereabouts of Dr Faisal Mostafa are unknown, although some unconfirmed reports say that he is in police custody in Bangladesh.
The weapons cache was found at an Islamic school, or madrassa, allegedly run by a charity based in Manchester.
The UK's Charity Commission is investigating the allegations.
Newspaper reports in Britain say that Dr Mostafa - the head of the Green Crescent charity which runs the madrassa - had previously been tried for plotting explosions in the UK.
Many people are educated by madrassas across Bangladesh
He was cleared in 2002 of planning to cause terrorist acts by using high explosives.
In November 2008 Dr Mostafa was found guilty by a court in Manchester of possession of dangerous weapons and making a false statement about baggage cargo at the city's airport.
A court spokeswoman told the BBC he was given a two-year suspended sentence and ordered to do 100 hours unpaid community work.
Bangladeshi police say that the arms haul - which included weapons, bomb-making equipment, bullets and booklets about jihad - was found in the coastal district of Bhola, about 100km (60 miles) south of Dhaka this week.
No-one at the charity, based near Manchester in north-west England, has so far commented on the allegations.
On Wednesday the UK Charity Commission said it wanted to find out "whether or not the charity, its funds, or funds raised on its behalf were used unlawfully".
The commission's website said that in 2008, Green Crescent had a turnover approaching £70,000 ($102,733).
British newspapers say that Dr Mostafa is a chemistry graduate. He is listed as a trustee for the charity on the commission's website.
According to the charity's website, Green Crescent is involved in other projects around Bangladesh and at least one in Pakistan.
In 2002, Dr Mostafa, from Stockport in the north of the UK, was cleared by a jury after being accused of conspiring to build home-made explosive devices using a "terrorists' handbook" detailing bomb-making techniques.
He faced a joint charge at Birmingham Crown Court of conspiracy to cause explosions with intent to endanger life and cause serious injury to property in the UK by stockpiling bomb-making material.
Bangladeshi officials say that the madrassa is located on a remote river island only accessible via a drawbridge.
They have described the premises as a "mini-ordnance factory" and said the whole compound was being used for militant training.
Police in Bhola say a leading member of the Jamayetul Mujahideen Bangladesh (JMB) extremist group was arrested in the raid along with three other people in a raid on Tuesday.
The JMB carried out a series of bombings across the country in 2005 and is blamed by some in the government for a mutiny last month which killed 74 people.
Bangladesh has in recent years been hit by a number of bomb attacks at political rallies, in courts and at cultural venues.