INDIANAPOLIS (AP) _ A man charged with plotting to kill a witness who could testify against him in a deadly Indianapolis house explosion apparently believed eliminating the witness was his ticket out of jail.
 
  A probable cause affidavit released Thursday says Mark Leonard told an undercover ATF agent that authorities would have to release him quickly if the witness recanted his testimony about Leonard’s involvement and was then killed.
 
  Marion County Prosecutor Terry Curry has charged Leonard with conspiracy to commit murder in the plot.
 
  Leonard, girlfriend Monserrate Shirley and brother Bob Leonard also face trial on murder and arson charges. Investigators say they allowed Shirley’s house to fill with gas and set a microwave timer to detonate it.
 

  The Nov. 10 explosion killed two people and damaged or destroyed dozens of homes.