In a probable cause affidavit released Wednesday, police describe Johnson's refusal to stop for a Howard County Sheriff's Deputy, who clocked him going 100 miles per hour on U.S. 31.
According to the affidavit, Johnson led police on a high-speed chase through several fields – at one point striking a house and nearly hitting two officers' vehicles – before running a stop sign and crashing into a car on County Road 300 South.
Two passengers inside that vehicle, 82-year-old Mary Jo Dimit and 73-year-old Nancy Cripe, were both killed as a result of the collision.
Friends who knew the pair said they were sisters who were "always together."
Police said Johnson initially claimed he wasn't the driver of the vehicle, but eventually admitted both to driving and to using marijuana and alcohol prior to the crash.
Johnson was initially arrested on two counts of OWI causing death, two counts of resisting law enforcement causing death and failure to stop after an accident.
On Wednesday, Howard County Deputy Prosecutor Scott McClelland filed two counts of reckless homicide against Johnson. Each charge carries a possible sentence of 1-6 years and a possible fine of up to $10,000.