Authorities say a journal left by ambush suspect Eric Frein provides a “cold-blooded and absolutely chilling account” of the night he allegedly opened fire outside a Pennsylvania State Police barracks, killing one trooper and injuring a second.

Frein wrote that he saw his shot and took it, watching from a distance as his victim, Cpl. Bryon Dickson, dropped to the ground.

Authorities found the multipage journal in a bag of trash at a wooded campsite they believe was used by the 31-year-old suspect. The document describes how Frein fled the shooting scene in a Jeep, but inadvertently ran into a retention pond and took off on foot — a botched getaway he termed a “disaster,” according to a police affidavit filed Wednesday.

Frein is charged with first-degree murder and other offenses in the Sept. 12 ambush that killed Dickson and wounded Trooper Alex Douglass. Law enforcement officials have been looking for Frein, described by authorities as a survivalist and marksman with a grudge against law enforcement, in the woods around his parents’ home in the Pocono Mountains.

The journal was found Sept. 29 in a hastily abandoned campsite along with explosives, ammunition, food, clothing and a water bottle whose DNA matched Frein’s, according to the affidavit.