Police say Caldwell waited in the driveway of Lamm's home about 15 miles west of Bloomington and shot him when he arrived. Caldwell has been jailed since being arrested Monday in Indianapolis.
Court records don't yet list a defense attorney for him.
County Prosecutor Jarrod Holtsclaw tells The Herald-Times (http://bit.ly/1mMh98m ) that another man arrested in connection with the attack won't be charged. Holtsclaw says investigators found no evidence that 41-year-old Kevin Caldwell was involved.