Treman Park on North Twin Lake in Calhoun County remains closed this (Tuesday) morning following a reported drowning on Monday evening. First responders were dispatched to the lake shortly after 5 p.m. after a caller reported a 25-year-old male swimmer had gone under and did not reemerge. A half-dozen local agencies, including the Rockwell City, Twin Lakes and Manson Fire Departments, Calhoun County Sheriff’s Office, Iowa State Patrol, and Buena Vista County Emergency Management Dive Team, responded to assist in the search. They called off their efforts Monday around dusk, but the search is expected to resume Tuesday morning. Treman Park will be closed to the public until further notice while operations are underway.