CHICAGO >> A suburban Chicago college student who was accidentally killed during a hammer throw event was struck by an errantly thrown hammer while standing near the field during warmups, authorities said today.

The hammer — a steel wire attached to a heavy metal ball that can weigh as much as 16 pounds — struck 19-year-old Wheaton College freshman Ethan Roser in the head during Saturday’s meet, said Bill Murphy, Wheaton’s deputy police chief. Roser, of Cincinnati, was volunteering at the meet and was going to measure the throws.

An autopsy conducted today by the DuPage County Coroner’s office determined, as expected, that the preliminary cause of death was head trauma.

Murphy said investigators would continue to look into whether there was any criminal negligence, but that they don’t suspect there was any. Wheaton College declined to say whether it would conduct its own investigation.

Students at the Christian college about 25 miles west of Chicago gathered after the meet to pray for Roser, who transferred there in January from a school in Cincinnati.

“It was time for us to come together and really turn to God in this tough time,” student Phoebe Morris told the (Arlington Heights) Daily Herald.

Roser spent much of his childhood in Zimbabwe, where his parents were missionaries, and he was deeply religious. His mother, Pat Roser, said Ethan’s faith played a big role in how he dealt with a leg injury in high school and in his decision to attend Wheaton.

“That just totally changed him, and he wanted to go and tell other young people about God,” she told the newspaper. “That’s what he was doing at Wheaton.”

Roser’s father, the Rev. Mark Roser, described his son as “just a really special kid” who considered his family members to be his best friends.

“We’re having a really hard time saying goodbye and letting go,” he told the paper. “We know God’s in control, and he works everything out even though it’s beyond our comprehension.”