Seven hours before the statute of limitations was set to expire, Pennsylvania Attorney General Josh Shapiro announced criminal charges against the Amtrak engineer for the fatal derailment that killed eight people on May 12, 2015. Philly.com called the charges a "stunning turn for a case that seemed all but concluded earlier this week."

Shapiro said in a statement, "Shortly after 5 pm, my office filed criminal charges against Brandon Bostian, the engineer of the Amtrak 188 train. These charges include 8 counts of involuntary manslaughter, one count of causing or risking a catastrophe and numerous counts of reckless endangerment, which go beyond what was included in the private criminal complaint ordered by Philadelphia Municipal Court President Judge Marsha Neifield."

Amtrak 188 was heading from Washington D.C. to New York City when it derailed outside of Philadelphia around 9:30 p.m. Later, it was discovered that the train was going 106 mph, more than double the 50 mph speed limit to manage a sharp turn at Frankford Junction.

At the time of the derailment, Philadelphia Fire Department Deputy Commissioner Jesse Wilson said, "I've never seen anything so devastating. They're in pretty bad shape. You can see that they're completely, completely derailed from the track. They've been destroyed completely. The aluminum shell has been destroyed and they've been overturned completely... I don't want to speculate on the cause but it's a devastating scene."

A passenger told the AP, "The front of the train is really mangled. It’s a complete wreck. The whole thing is like a pile of metal."

On Tuesday, the Philadelphia district attorney's office declined to prosecute Bostian. That sent victims' families seeking justice; from the NY Times:

On Wednesday, lawyers for 32 victims asked the district attorney’s office to accept a criminal complaint filed by the family of Rachel Jacobs, a woman killed in the crash. The district attorney’s office declined.

Thomas R. Kline, a lawyer for the Jacobs family, said he was worried the district attorney’s decision left no other recourse for charges. But then a former city prosecutor, Richard A. Sprague, called him and told him about another option, using an obscure Pennsylvania law, Mr. Kline said.

The law allows anyone to file a private criminal complaint in municipal court requesting misdemeanor charges against someone. In Pennsylvania, involuntarily manslaughter and reckless endangerment are misdemeanors.

On Wednesday, Mr. Kline and other lawyers for some victims’ families went to the Philadelphia Municipal Court and filed the private complaint against Mr. Bostian. On Thursday, Judge Marsha H. Neifield accepted the complaint and ordered the district attorney’s office to reverse its decision and charge Mr. Bostian with involuntary manslaughter and reckless endangerment.

The Philadelphia district attorney's office said it couldn't charge Bostian, claiming a conflict of interest, and then kicked it over to Attorney General Shapiro.

The complaint states, "Involuntary manslaughter is when, as a direct result of the doing of an unlawful act in a reckless or grossly negligent manner, or the doing of a lawful act in a reckless or grossly negligent manner, he causes the death of another person. TO WIT: On May 12, 2015, Brandon Bostian, the engineer of Amtrak Train No. 188, was traveling a route he navigated many times. When approaching a curve at the Frankford Junction, instead of decelerating the speed, Mr. Bostian accelerated the speed to more than twice the legal limit. Mr. Bostian, as the operator of the train, was not able to navigate the curve at such a high rate of speed. This caused the train to derail. This derailment caused the deaths of eight passengers."

Bostian has claimed no memory of the incident. The National Transportation Safety Board believes he was distracted by radio transmissions before the derailment (here's the NTSB report).

Positive train control, which can slow or stop a train in certain areas, was in place on the southbound tracks, but not on the northbound tracks at the time of the derailment.