The Philadelphia District Attorney's Office announced Tuesday that it would not file criminal charges against the Amtrak engineer operating the train during the May 2015 derailment in Philadelphia that killed eight and injured 200 more.

After an investigation by the office's homicide unit of Train 188's derailment in the Port Richmond section of Philadelphia, investigators found that while the accident was caused by excessive speed, no crime had been committed by engineer Brandon Bostian.

“We cannot conclude that the evidence rises to the high level necessary to charge the engineer or anyone else with a criminal offense,” the office said in a statement Tuesday.