A camp that was supposed to be a shelter from terrorism and violence instead became an instant death zone for dozens in Nigeria this week, CNN reports.

At least 58 people were killed and another 78 injured when two female bombers detonated their suicide vests, according to emergency relief officials. The victims were in a camp for people who had been displaced by Boko Haram violence in Nigeria's Borno State.

As horrendous as the attack was, it could have been worse. One of the bombers backed out at the last minute.

"There were three female bombers who entered the camp around 6:30 am local time disguised as displaced persons. Two of them set off their explosives in the camp while the third refused after realizing her parents and siblings were in the camp," said Satomi Alhaji Ahmed, head of the Borno State Emergency Management Agency.

The bombers struck Tuesday, Feb 9, at the camp in the town of Dikwa, Ahmed said. Dikwa is in northeastern Nigeria, near the border with Cameroon.

More than 53,000 people fleeing Boko Haram attacks from six districts are sheltering under military protection.

The suspect confessed she and the two bombers were sent by Boko Haram to attack the camp, warning more bombers were on their way, Ahmed said.

"She told the military officers who interrogated her that they were among several women detailed by Boko Haram to attack the camp. She warned more attacks were underway as the female bombers would sneak into the camp in different guises," Ahmed said.

The attacks are believed to be reprisals for the recent military offensive against Boko Haram in strongholds along the border with Cameroon, a military source said.

Last week, troops raided the three Boko Haram strongholds, killing more than 100 fighters and freeing more than 1,000 people -- including more than 100 women kidnapped and used as sex slaves by the insurgents, said the military source on anonymity.

The source, according to CNN, said the freed women were brought to the Dikwa camp and that Boko Haram terrorists "are pained by that, and hence their decision to send in suicide bombers in revenge.

Boko Haram is a militant Islamic group working out of Nigeria and in the border areas of Chad and Cameroon; its purpose is to institute Sharia, or Islamic, law. Boko Haram militants mainly inhabit areas in the northern states of Nigeria, including Borno. The group has received international condemnation and notoriety for its brutality and mass kidnappings of women and girls.