DENVER – The search for a missing man who was celebrating his 21st birthday on the South Platte River Saturday has been suspended. Sheridan police were called to an area north of West Union Avenue around 4:30 p.m. Saturday. Witnesses stated a man fell from an inner tube and was swept down the river. Several people tried to pull the man from the water but the fast-moving current prevented their rescue efforts.”The victim was last seen about one quarter mile north of Union Avenue floating in the river,” according to a press release from the Sheridan Police Department. Authorities searched for several hours Saturday evening and were not able to find the man.On Sunday, Denver Fire personnel floated the river from the area where the victim was last seen to approximately West Hamilton Place. The Arapahoe Rescue Patrol searched the river banks on foot and on ATVs from just north of West Union Avenue to north of West Florida Avenue. Search efforts ended early Sunday afternoon. The Sheridan Police Department identified the missing man as Joseph Goodwin. Sheridan Police are discouraging any type of tubing or rafting activities in the Platte River within the city limits, due to swift water conditions. Copyright 2015 Scripps Media, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.