Nairobi — Anti-terror police have sought the help of Immigration officials in interrogating a man they are holding in connection with last week's explosion in Nairobi.

Mr Ahmed Farah Hirsi, who presented himself to police last Sunday, was yesterday questioned by Immigration officials.

Police are seeking to establish his movements in and out of the country for the past several years.

Sources close to the investigations, however, indicated police had not yet arrested the people who detonated an explosive outside the City Gate Restaurant.

They are investigating Mr Hirsi and another man believing could help in tracking down the perpetrators of the 8.30am explosion that killed a man and injured 39 others.

On Wednesday, police released images of people they believe could help in unravelling the explosion mystery.

Sketches of the faces of the two men, and another of the man who died in the blast, were produced by an artist who was engaged by detectives and were published in newspapers yesterday.

Records at the University of Nairobi showed Mr Hirsi completed a masters degree in Religion in 2002 at the institution.

Mr Hirsi had also been awarded the first degree in Arabic language at Somalia National University in 1990.

He claimed he was born in Mandera Central in Kenya but detectives doubt since the man is not eloquent in either English or Swahili language.

Police spokesman Eric Kiraithe appealed to the public to volunteer more information to police.