Abuja - The alleged mastermind of the kidnapping of a Briton and an Italian in Nigeria who were killed last week amid a rescue attempt has died after suffering gunshot wounds in a raid, police said Wednesday.

Nigeria's secret police announced the death in a statement that also for the first time officially described in detail the events surrounding the murder of the two hostages on March 8.

“Abu Mohammed died on 9th of March 2012 following severe bullet wounds sustained during the Zaria raid,” a statement from Nigeria's secret police said, referring to a March 7 raid that led to his capture.

It also said “investigations revealed that the plot was masterminded by the Abu Mohammed-led faction of (Islamist group) Boko Haram in Nigeria”.

The two hostages were killed in the northwestern Nigerian city of Sokoto on March 8 after being kidnapped nearly a year earlier and as a joint British and Nigerian rescue operation sought to save them.

The secret police described a series of events that led the guards of the foreigners, who were kidnapped in May 2011, to kill them “before the arrival of security forces”.

According to the statement, a raid was conducted in the northern city of Zaria on Wednesday, March 7 - a day before the rescue operation - leading to the arrest of Abu Mohammed and five others.

During the Zaria raid, a soldier was killed “and his throat slashed”, secret police said, while another security agent was seriously wounded. Abu Mohammed along with other suspects was also shot and wounded, it said.

“Preliminary interrogation of the arrested suspects revealed that the guards protecting the two foreign hostages in Sokoto had been directed to kill them in the event of any envisaged threat,” it said.

“The arrested suspects therefore advised that a rescue operation be immediately initiated, moreso as one of them had escaped during the Zaria raid.”

The joint operation was then launched, it said, with the suspect who killed the soldier in Zaria leading the security agents to Sokoto.

They arrived early on March 8 - about 4:30 am - and other security operatives had already searched and cordoned off the area to prevent the hostages from being smuggled out, the statement said.

It said that the guards of the hostages, apparently acting on a directive from the suspect who escaped the Zaria raid, killed the two foreigners.

The guards were however unable to leave the house in Sokoto where the hostages were killed because security agents had already blanketed the area, according to secret police. A gun battle broke out when security forces arrived at the building.

During the shooting, “three of the guards were killed while the wife of one of them sustained bullet wounds and was rushed to the hospital”, the statement said.

“No lives were lost on the part of security forces though some service personnel sustained gunshot injuries.”

The statement announced the arrest of six people in connection with the incident, including Abu Mohammed.

It also spoke of the arrests of three other suspects “who were discovered to have conducted surveillance on the victims before their abduction”.

The suspects, with the exception of Abu Mohammed, were presented to journalists on Wednesday. One appeared to have head wounds and was bandaged, but the nature of the injury was not clear.

The failed rescue mission authorised by British Prime Minister David Cameron sparked a diplomatic row between London and Rome, which complained that it was not consulted about the operation beforehand.

Nigeria's government and security agencies have also come under heavy pressure over the incident, and many have expressed doubts over their claim that Boko Haram was behind the kidnapping.

The Islamist group has carried out scores of bombings and shootings in Nigeria, but had not been previously known to conduct kidnappings. A purported spokesman for the group has denied responsibility. - Sapa-AFP