A man injured in a multi-vehicle Mission District crash has died, but police still aren't sure if it was the collision, or something else, that killed him.

It was 5:23 p.m. Sunday when a man the Chron describes as "elderly" drove into oncoming traffic at the intersection of 18th and Guerrero Streets.

At least four vehicles crashed as a result, ABC 7 reports. According to San Francisco Police Department spokesperson Officer Carlos Manfredi, the man had suffered an unspecified "medical emergency," likely the reason he drove into traffic in the first place.

He was pronounced dead at the scene, but Manfredi says police still don't know if the man's death was caused by the injuries he sustained in the crash or by the medical emergency, itself.

“It is unclear if he died due to the collision, or the medical condition,” Manfredi told the Ex.

As of publication time, the San Francisco Medical Examiner's office had not publicly identified the dead man, nor did they have any additional details on his cause of death.

KTVU reports that the driver and passenger of the vehicle the deceased man struck suffered minor injuries, and "two others involved were treated for non-life threatening injuries, and are expected to be OK."