"After a thorough consideration of all of the available information about the case, it is determined that the admissible evidence and available witnesses would likely be insufficient to meet the burden of establishing beyond a reasonable doubt that Mr. Busch committed a crime during the Sept. 26th incident," the Delaware DA's office said in a statement.
At this stage, it's unclear when NASCAR will reinstate Busch, who was suspended indefinitely on February 20. ESPN reports the company has retained a domestic violence expert to come up with guidelines for the 2004 series champion's return.
The 36-year-old embattled racer has been hounded by Driscoll's allegations following a dispute after the September 2014 race at Dover International Speedway. Driscoll claimed Busch expressed suicidal thoughts before slamming her head against the wall of his motorhome following his elimination from the 2014 Chase for the Sprint Cup.
Since the November 2014 court filing, the investigation has taken a number of bizarre turns, with Busch accusing Driscoll of being an assassin and lawyers claiming she lied on the stand, while a California congresswoman called for NASCAR to suspend the star driver. That eventually did happen. The state of Delaware issued an order of protection against Busch, while his legal team was unable to overturn NASCAR's indefinite suspension, meaning he missed the opening race of the 2015 season, the Daytona 500.