Kayla Mueller , 26 , was captured by ISIS in August of 2013 in Aleppo , Syria . Was held for 18 months before being killed last month , likely by airstrike . International aid worker was honored in hometown of Prescott , Arizona . Emotional father said daughter 's purpose was to ease suffering of others . Three people attended Saturday service including Arizona Sen. John McCain .
Kayla Mueller , 26 , was captured by ISIS in August of 2013 in Aleppo , Syria . Was held for 18 months before being killed last month , likely by airstrike . International aid worker was honored in hometown of Prescott , Arizona . Emotional father said daughter 's purpose was to ease suffering of others . 500 people attended Saturday service including Arizona Sen. John McCain .