The officer, who was at the camp for displaced people in Dikwa, Borno state, when two other women blew themselves up on Tuesday, killing 58, said the third was spotted as she tried to leave.
"The Kanuri women are known for plaiting their hair but we realised over time from the bodies of female suicide bombers that they all had ponytails," he told AFP on condition of anonymity.
"Based on that we came to the conclusion, after a thorough investigation and the testimonies from female bombers arrested alive, that before going on suicide bombing they are made to wear a ponytail because in Kanuri traditions when a woman dies before she is buried her hair is loosened and made in to a ponytail.
"So, when we saw her fleeing the camp with a ponytail, we just knew she was one of the bombers, so we arrested her and she confessed."
More From This Section
Many women wear a long hijab covering their head in the Muslim-majority north but the officer, who was involved in the arrest, said hers had slipped in the panicked aftermath.
The carnage at the camp, which houses more than 50,000 people who have fled nearly seven years of violence in the region, was the latest in a string of attacks against civilian targets.