OAK PARK, Ill. (CBS) — Loved ones honored a young diplomat from River Forest on Tuesday at her former high school, three days after she was killed in a Taliban bombing in Afghanistan.

CBS 2’s Susanna Song reports a memorial mass was held for 25-year-old Anne Smedinghoff at Fenwick High School, from which she graduated in 2005.

A former teacher described Smedinghoff as “serenely beautiful,” “calm in all situations,” and someone who “had a quiet intelligence.”

Two of her siblings, who also graduated from Fenwick, attended the memorial mass.

The auditorium at Fenwick was packed with students, some of whom had met her two months ago when she visited her alma mater to talk to students in their world history class.

A group of priests led the mass, praying for Smedinghoff and her family.

The 25-year-old foreign officer for the State Department was killed in Afghanistan on Saturday in a suicide bombing. She and four other Americans who died in the attack were on their way to deliver books to a school when their convoy was rammed by a vehicle filled with explosives.

The other Americans killed in the attack were three soldiers who were protecting Smedinghoff, and a Defense Department translator. Their identities have not been released as of Tuesday morning.

Smedinghoff had been a diplomat for the past three years, after graduating from Johns Hopkins University. Before going to Afghanistan, she had worked in Venezuela. U.S. Secretary of State John Kerry met her two weeks ago in Kabul, Afghanistan, and said she was everything a foreign officer should be.

Irene Drago, one of Smedinghoff’s former teachers, said ever since the 9/11 terrorist attacks, Smedinghoff knew her calling was to help others.

“For one so young, she seemed so focused, and determined to unravel the big problems,” Drago said. “At the same time, she had the gentleness and patience required to assemble and send care packages to our troops serving in Iraq and Afghanistan.”

Smedinghoff’s body was returned to the U.S. at Dover Air Force Base on Monday. Her parents greeted the casket. Funeral arrangements for Smedinghoff have yet to be announced.