Police say a local gas-station employee called them Tuesday night after a 44-year-old man couldn't pay for his gas.
The responding officer ran a check on the man and found he was wanted by probation and parole officials — but the man sprinted to the Wisconsin River and dove in.
Officials searched Tuesday night and much of Wednesday, bringing in cadaver dogs to search the shorelines.
Prairie du Sac Fire Chief Jim Hambrecht says the river's current is strong and swift, and it would be difficult for a good swimmer to get across. He says there are logs and debris in the water, making diving and swimming dangerous.
Searchers say the water temperature was 74 degrees.