Prosecutors announced Tuesday they will not level criminal charges at Brandon Bostian, the engineer involved in the 2015 Amtrak derailment that killed eight people and injured some 200 others in Philadelphia.

"The evidence indicates that the derailment was caused by the engineer operating the train far in excess of the speed limit," the Philadelphia District Attorney's Office said in a statement. "However, we cannot conclude that the evidence rises to the high level necessary to charge the engineer or anyone else with a criminal offense."

The National Transportation Safety Board concluded in August 2016 that Bostian likely caused the derailment, which occurred as the engineer accelerated into a curve rather than braking. The New York-bound Amtrak 188 entered the curve going more than double the speed limit, flinging multiple train cars free from the tracks and tearing up some of the railway's I-beams.

Yet prosecutors say they have "no evidence that the engineer acted with criminal 'intent' or criminal 'knowledge,' " and they do not believe there's enough evidence to prove that Bostian acted with "criminal recklessness."

So the office has concluded its investigation into the incident, which also prompted more than 125 lawsuits.

As NPR's Merrit Kennedy reported in October, a federal judge approved a $265 million dollar settlement between Amtrak and people affected by the crash:

"The court documents state that the settlement program is also available to passengers who have not yet filed a lawsuit or settled with Amtrak. According to the terms of the settlement, plaintiffs will be notified of their final award by June 30, and plaintiffs' lawyers expect the claims payments to be distributed by next summer."

Bostian also sued Amtrak for negligence in January, according to member station WHYY, which says the engineer claimed he came "under attack by projectiles" on the night of the crash. But WHYY reports that federal investigators "found no evidence that Amtrak 188 had been targeted or hit by rock-throwers."

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