Prosecutors have now dropped all charges against the pilots of two jon boats who crashed killing four young adults in Burlington last year.
Officials say the boats collided while shuttling people to and from a party on the Mississippi River.
Burlington residents 21-year-old Joseph Schier and 22-year-old Douglas Metcalf were each charged with one count of operating a motorboat while intoxicated causing death and four counts of involuntary manslaughter in December of 2012.
Charges against Schier were dismissed in June and charges against Metcalf were dismissed Tuesday.
Attorneys say the state was unable to prove the charges beyond a reasonable doubt.