RAPID CITY, S.D. (AP) — Searchers are looking for a missing hunter in western South Dakota.

Pennington County authorities say 66-year-old Larry Genzlinger of Howard was last seen Tuesday afternoon. Genzlinger was hunting elk with his nephew near Deerfield Lake.

A sheriff’s spokeswoman tells the Rapid City Journal that Genzlinger and his nephew separated, but that Genzlinger never returned to their planned meeting spot.

The nephew called 911 Tuesday night to report Genzlinger was missing. Searchers looked for Genzlinger until early Wednesday, then resumed the search that morning. Authorities say a helicopter was taken up for about 20 minutes but stopped its search due to fog.

Authorities say Genzlinger is diabetic and has been without food and insulin for 24 hours.