By ADAM NOSSITER
Published: October 2, 2012

BISSAU, Guinea-Bissau — Assailants killed at least 25 people at a college in northeastern Nigeria early Tuesday, the Nigerian police said. But while the Islamist sect Boko Haram has killed hundreds of people in the region over the last year, suspicion this time appeared to be focusing on a campus election on Saturday that was bitterly contested along religious and ethnic lines.

“Most of the people killed were executive leaders that were elected,” said the police commissioner for Adamawa State, Godfrey Ameka Okeke. “We cannot exonerate the students completely.”

Some fraternities at Nigerian colleges have been using gang violence to exert their power, The Associated Press reported, quoting a statement by Yushau Shuaib, the spokesman for Nigeria’s National Emergency Management Agency, that also focused on campus politics as a possible cause of the massacre.

A spokesman for the college, the Federal Polytechnic in Mubi, could not be reached; communications are difficult in the area because Boko Haram has blown up many of the region’s cellphone towers. But the group is known more for targeting two or three members of the government, army or police at a time.

Mubi, which is in Adamawa State, has been under an afternoon-to-morning curfew because of the Boko Haram-related violence, and the campus killings took place during the early morning.

The attackers “were selective in their operation,” Mr. Okeke said. “They had the names of the victims. When they entered the compound, they asked everybody to come out. Then they locked all the doors.

“After they asked the names, they took them aside and shot them,” Mr. Okeke said, although many were reportedly spared.

“How should they know their names?” he added. “This is what we want to know, whether it was related to the elections.”

There were differing accounts of the death toll. College authorities reached by The Associated Press reported that 27 students had been shot or stabbed to death, while a spokesman for the Adamawa state police, Ibrahim Muhammad, told the agency that 25 had been killed — 19 polytechnic students, three students of another college, a former soldier, a guard and an elderly man.

There was at least one other theory about the attack. Last week the police raided the campus looking for Boko Haram suspects — an increasingly frequent occurrence in a part of Nigeria where the security services have been battling the sect. The police confiscated numerous weapons and improvised explosive devices, and they made several arrests. Local journalists suggested that the killings could have been related to that raid.