Police in Nigeria say a man they have in custody has confessed he took part in the assassination Sunday of Justice Minister Bola Ige.

The man who police say confessed to taking part in the killing of Justice Minister Bola Ige is among several who have been apprehended since the attack Sunday. Officials say the man, whose name was not released, turned himself in to authorities on Wednesday.

Those in custody include at least two members of the Justice Minister's security detail. Nigerian police say a number of other people have been apprehended and are cooperating in the investigation.

Investigators say they have drawn what they say is useful information from the man who allegedly confessed. But they say they are still far from knowing the motive behind the killing. The government has posted a reward of more than $4,000 for information that would help solve the case.

Bola Ige, a close political ally of President Olusegun Obasanjo, was gunned down at his home in the southwestern city of Ibadan late Sunday. Family members say gunmen stormed into his bedroom, opened fire at close range, and fled.

Mr. Ige's assassination came amid a festering political crisis in southwestern Osun state. The state's governor, Bisi Akande, has been at odds with his deputy governor. Both men belong to Bola Ige's Alliance for Democracy Party. The impasse has resulted in street clashes between supporters of the two men. Last week, a state lawmaker who was an outspoken supporter of the deputy governor was killed.

Political observers say the minister had taken the side of Governor Akande in the dispute.

The assassination prompted President Obasanjo to call an emergency meeting of his cabinet and the heads of Nigeria's armed forces on Monday. The meeting ended with a call for the deployment of troops to Osun state to avert any possible violence in the wake of Mr. Ige's death.

The Nigerian Senate had been on a Christmas recess but has been called to convene in an emergency session on Friday. Lawmakers are expected to discuss a response to the minister's assassination.