At least 11 parents whose children were kidnapped by the terrorist group Boko Haram in mid-April have died, according to the Associated Press.

Seven fathers died during a recent Boko Haram attack on the village of Kautakari. The fathers were among 51 who died in that attack.

Four more parents have died of natural causes, including heart failure and high blood pressure. The deaths are being attributed to the stress caused by the loss of their daughters.

“One father of two of the girls kidnapped just went into a kind of coma and kept repeating the names of his daughters, until life left him,” community leader Pogu Bitrus told AP.

More than 200 Nigerian schoolgirls were kidnapped three months ago and are still missing.