An explosion disrupted the 50th graduation ceremony at the University of Ibadan in Nigeria, minutes before the country's head of state, General Abdulsalami Abubakar, was scheduled to arrive.
The campus was thrown into confusion until an explanation was found - some students had set light to a custom-built, bullet-proof limousine, owned by Azeez Arishekola, a prominent arms merchant, who was a close business associate of General Abubakar when he was army chief-of-staff.
His security guards have been implicated in the killing of some students in May.
Mr Arishekola arrived at the university in an entourage of six cars packed with machine guns, pistols, grenades, ammunition and explosives.
Unaware of the vehicles' contents, students seeking revenge, set the cars on fire.
Mr Arishekola escaped, disguised as a student. When calm was restored, General Abubakar arrived at the ceremony, but made no mention of the incident. Police made no arrests.