The American hostage who died in Syria earlier this year, Kayla Mueller, passed up a chance to try to escape out of concern for another Western hostage, according to a report in Foreign Policy.

Mueller had been held captive by Abu Sayyaf, a senior Islamic State figure killed by members of Delta Force last weekend.

Mueller’s death was announced by the Islamic State on Feb. 6; they claimed she had died in a Jordanian airstrike, but that was never verified and some analysts doubted that was the way she died.

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Mueller was a humanitarian aid worker helping Syrian refugees in southern Turkey when she was taken hostage during a trip to Aleppo, in northwest Syria, on Aug. 4, 2013.

The hostage Mueller reportedly refused to leave behind was an older aid worker who had also been captured in 2013. Her name has not been publicized.

Sources told Foreign Policy that another hostage escaped sometime in late August 2014 but Mueller stayed behind because she did not want to abandon the older hostage. The fate of that woman is not known.