SIOUX FALLS, S.D. (KELO) — Investigators are searching for information on a Sioux Falls assault that left a man with life-threatening injuries.

When authorities found the 49-year-old victim Tuesday night in the central part of the city, he was unconscious but breathing.

He appears to have suffered a serious brain injury.

Police checked in on the victim Thursday morning, and his condition has not improved.

If you have information that could help with the investigation, contact police or crime stoppers.