When the news that Paul Otieno was being held on suspicion of killing his three-year-old son reached Archbishop Gilbert Deya's ministry last week, the congregation was shocked.

Otieno, 31, is a pivotal player in the ministry, running its successful global television channel.

He is also the adopted son of the Kenyan Archbishop infamous for claiming he is able to make infertile women conceive through the power of his prayer.

Gilbert Deya, 57, who has five children of his own, had brought up Otieno - actually his nephew - as his own son since his brother Wilson died when Otieno was a young boy.

Otieno, who came to the UK as an 18-year-old in 1996, is currently under police guard in hospital after his son, also called Wilson, was found stabbed to death last Monday at the family flat on the Lynton estate, Bermondsey.

Otieno's wife Jackline sustained a knife wound to the neck, although their 17-month-old daughter was unharmed. Otieno suffered stab wounds to the neck, chest and stomach and remains seriously ill.

The incident has left the church reeling, not least because it shines an unwelcome spotlight on the Deya Ministry, behind which lies an extraordinary story of fantasy, alleged fraud and child trafficking.

Set in the heart of south London, it is a tale which involves players now under investigation by the police in both Nairobi and London.

It is still unclear what happened at Otieno's flat last week, although there are rumours of marital tension.

What is certain is that he and Jackline play a central role in the life of the Deya Ministry - the television channel is key in expanding the church's brand worldwide.

According to Gakuru wa Macharia, who wrote the Archbishop's biography, Deya and the Miracle Babies, "Otieno is trusted by Deya more than his own sons. Jackline is the accountant at the ministry so Deya has more trust in them over his financial affairs than he does with his own children.

"In turn, because they were fully dependent on the church for money, they are more loyal to him than his own children.

"They are also more respectful to him than his sons and are integral to the operations of the church."

Within the ministry his reputation is good. A member of the church who has known Otieno "for many years" describes him as a "mildmannered guy, quiet and well-collected".

And despite reports that he was drinking as a result of marital problems, the source added: "He never drank alcohol. These reports are just not true."

Before last week's tragic events Otieno was involved in building what members claim is the fastest-growing religious brand in the UK.

There are 34,000 members of Deya's church, and the TV channel Deya Network Broadcasting, which goes out on Sky, reaches a huge audience.

Allegations of trafficking babies and an extradition warrant against Deya have done little to stop thousands pouring through the doors of his ministries.

They continue to believe, ever since the birth in December 1998 of the first "miracle baby", a boy born to a Stockwell woman whose fallopian tubes had previously been severed by doctors, that Deya has a spiritual power to make infertile women conceive.

Yet since 2004, Gilbert Deya has been subject to an extradition warrant issued by the Kenyan authorities.

He is wanted on five counts of abducting babies, illegally registering them and trafficking them to the UK.

His wife Mary and two other women - Miriam Nyeko and Rose Kiserem - were jailed for two years in May 2007 by a Nairobi court for stealing a child.

Mary completed her sentence last year but is now the subject of a fresh child trafficking investigation in Nairobi.

Just how many children may have been abducted remains a mystery. In 2004, 21 "miracle babies" were seized from Mrs Deya and another suspect, prompting 53 sets of parents to come forward claiming their children had been stolen.

Meanwhile, to resist his extradition warrant, Deya has claimed asylum in this country on the grounds that he would be politically persecuted in Kenya.

But video footage handed to the Standard appears to seriously undermine his argument. It shows Deya introducing Raila Odinga, now Kenya's Prime Minister, to Liberal Democrat MP Simon Hughes at his church in December 2007.

This video suggests that rather than being the target of sinister political forces in Kenya, Deya is a man well connected to the upper echelons of power in Nairobi.

He also appears to have done his best to make influential connections in the UK.

In 2002 he was introduced as a representative of Kenyan churches to the Queen and Prince Philip as part of the monarch's Golden Jubilee celebrations.

But not everyone he comes across is convinced.

"Deya's brand of religion is a combination of traditional African beliefs peppered with threats of curses and exorcism," says Gakuru wa Macharia, who describes the church as akin to a cult and has received death threats since publishing his book on Deya.

"Because there is no fixed regulation of 'charismatic' and spiritual churches, and many of the African churches such as Deya's fall into this category, becoming a pastor requires simply the ambition to become one.

"Many of the 'bishops' and 'archbishops' have achieved their status by buying or being favoured by those who own or run the ordaining organisations and do so simply for business reasons."

Deya, who lives in "an inner sanctum" in the church, is now widely reported to be a millionaire despite having arrived in the UK in 1996 on a missionary's visa with barely enough money to rent a preaching room.

Figures released by the Charity Commission show that in 2007 the total income for the Gilbert Deya Ministry was £1,174,309 (figures for 2008 are currently overdue).

It is Deya's capacity to harness the power of modern multi-media that offers the best explanation for the ministry's growing income.

His website offers "miracle" products such as cotton handkerchiefs, olive oil and prayer sheets, which Deya claims have been used to "unbelievably heal" the incurable, and asks members to make a minimum £2 a month standing order to an account at Barclays Bank in Hammersmith.

"Those who join the church are first threatened by curses or misfortunes that will befall them if they don't give money," says Gakuru. "They are told the money is to break this curse."

And then there is the TV channel which Otieno ran. The preaching room inside the Deya Ministry resembles more of a TV studio than a traditional place of worship.

A bank of lights is trained on the pulpit and cameras filming the preacher relay pictures to an editing suite in the middle of the room.

Much like a live television gameshow, at about 8pm on a prayers night, a "warm-up" preacher will whip up the congregation into a frenzy before the star act - Archbishop Deya - makes his appearance.

Anyone with Sky television can witness the thrice-weekly Deya Broadcasting Network's miracle hour on channel 595.

Deya, dressed in a sober black suit, rocks back and forth as members of the congregation step forward.

Baying by the congregation appears to create a magnetism between the archbishop and those seeking the miracle cure and Deya uses this energy to create the suggestion that the moment he touches the "patient", his spiritual force, like an electrical jolt, will drive the affliction away.

Earlier this year Ofcom issued Deya Broadcasting Network with a reprimand after it broadcast footage of a woman being "cured" of breast cancer.

Making such a claim without clearly stating that the woman in question was also receiving medical treatment for her condition contravenes its guidelines.

Ofcom acted when a viewer, disturbed by a scene showing the woman removing bandages around her breast after the "miracle" had been performed, made an official complaint.

Despite repeated attempts to contact Gilbert Deya, the archbishop did not answer our calls. The question is: how has he managed to remain in this country, evading justice in Kenya, for five years?

In December 2007, the then Home Secretary Jacqui Smith ordered his extradition. In October last year an appeal against extradition was dismissed. He sought leave to appeal to the House of Lords but this failed.

Deya has now been granted a stay on the grounds that his human rights would be infringed by conditions in Kenyan prisons.

This is despite the fact that Amnesty International has no records of maltreatment in Kenyan prisons.

The Home Office is currently investigating these claims and until the Home Secretary makes a decision, Deya is free to continue preaching in the UK.

Home Secretary Alan Johnson may now want to ponder the tragedy that befell Otieno's family this week when he considers Archbishop Deya's extradition case.

But he may also want to consider the plight of the scores of parents in Kenya who have had their babies stolen and suspect this highly charismatic religious fanatic had a hand in their disappearance.

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