An oncoming Audi A8 driven by a 56-year-old man then struck the vehicle and Buller, who was pronounced dead at the scene, police said.

The driver of the Ford E-350 stayed and cooperated; his passengers, an 8-year-old boy and a 44-year-old woman, and the driver of the Audi were taken to a hospital in stable condition, police said.

Buller studied ways to protect against viruses if they were ever used as weapons of bioterrorism, SLU’s obituary said. His expertise was frequently sought after the 9/11 attacks caused concern the smallpox virus could be used as a biological weapon.

He started at SLU in 1994. He was set to retire in 2018.

In addition to his work at the university, Buller volunteered with Habitat for Humanity, sponsored impoverished children in other countries, and often donated to Wounded Warriors.

He was an active member of Our Lady of Lourdes parish in University City, where he lived with his wife, Joslyn.

Meghan Buller said visitation will be at 9:30 a.m. Saturday at Our Lady of Lourdes church, 7148 Forsyth Boulevard. A Mass will be celebrated at 11 a.m., followed by a reception at noon.

The SLU School of Medicine also plans to have a memorial service at a later date.