Friends, family, colleagues and strangers offered an assortment of tributes Saturday when the family of Kayla Mueller, the 26-year-old aid worker whose death in Syria was confirmed last month, hosted a public memorial to celebrate and commemorate her life in Prescott, Arizona.

"The girl knew she had a purpose," said Todd Geiler, who has known the Mueller family for at least two decades, reported. Describing Kayla Mueller as someone who always rooted for the underdog, Geiler said, "This was the basic fiber of her."

Mueller's colleagues at a Turkey-based aid organization, as well as other humanitarian-aid workers, added to the tributes via video. Some quoted a sentence Mueller uttered during a talk she gave about conditions endured by Syrian refugees while visiting home in 2013: "I will not let this suffering be normal."

Mueller grew up in Prescott and graduated from Northern Arizona University in Flagstaff. Her last visit home was in May 2013. Less than three months later, she was kidnapped in Syria and held hostage by the Islamic State group for 18 months. The militant group said she was killed in an airstrike conducted by the Jordanian military, but the U.S. government has maintained the group itself is responsible for her death.

The memorial was held at Yavapai College in Prescott. The program included a prerecorded reading by Kayla Mueller's mother, Marsha Mueller. It quoted a letter her daughter had written as a hostage: "Only in your absence have I finally at 25 years come to realize your place in my life," she wrote about her family.

At the memorial, the aid worker's brother, Eric Mueller, and father, Carl Mueller, invoked Kayla Mueller's preference for bright colors. During the ceremony, her brother donned a blue and purple tie, while her father revealed rainbow-colored suspenders and socks. "I found these things in Kayla's room," the latter said.

U.S. Sen. John McCain of Arizona spoke at the memorial, too. "I didn't have the privilege, the blessing, of knowing Kayla," he said. "I wish I had." The senator had been in contact with the Mueller family while Kayla Mueller was being held hostage. In February, he said he had "failed" to rescue her. It emerged in February that there had been several attempts to rescue Mueller -- her family even wrote to President Barack Obama to ask for a prisoner swap -- but the efforts ultimately failed.