PHILADELPHIA (AP) — Philadelphia prosecutors say the speeding Amtrak engineer involved in a derailment that killed eight people and injured about 200 others won’t be charged.

They said Tuesday they can’t prove engineer Brandon Bostian acted with “conscious disregard” when he accelerated the train to 106 mph on a 50 mph curve.

Federal investigators concluded that Bostian lost track of his location before the May 12, 2015, crash after learning a nearby commuter train had been struck with a rock.

Victims’ lawyers Tom Kline and Robert Mongeluzzi describe their clients as bitterly disappointed and say many remain in constant pain two years later.

Kline believes the engineer should at least face reckless endangerment charges.

But District Attorney’s Office says there’s not sufficient evidence to prove he consciously disregarded the risk.