Two female suicide bombers linked to Boko Haram blew themselves up this week in a displacement camp meant to serve as shelter from the Nigerian terrorist group, killing more than 60 people and wounding dozens more. A third potential bomber refused to detonate her explosives after she discovered that her family was in the camp.

“There were three female bombers who entered the camp around 6:30 a.m. [on Tuesday] disguised as displaced persons,” said Satomi Alhaji Ahmed, head of the Borno State Emergency Management Agency, according to CNN. “Two of them set off their explosives in the camp while the third refused after realizing her parents and siblings were in the camp.”

The refugees fled a previous attack by Boko Haram — the name meaning “Western education is forbidden” — and the woman who failed to detonate her explosives told interrogators that the terrorist group is planning more attacks via female suicide bombers in response to raids on Boko Haram strongholds by Nigerian troops.

The terrorist group — which has been labeled the world’s deadliest, even worse than the Islamic State — has a history of using women as suicide bombers. Elizabeth Pearson, a gender and radicalization researcher in defense studies at King’s College London, told the Huffington Post last year that while some women genuinely subscribe to Boko Haram’s philosophy and violent means, many are coerced into becoming suicide bombers.

“A 13-year-old girl arrested in December said she was coerced into carrying out a suicide attack by her father, who she described as a Boko Haram supporter,” she said then. “Another female suicide bomber last November was reportedly accompanied by two men, suggesting there may have been an element of doubt that she would go through with it.”