Eric Matthew Frein was born on May 3, 1983, in New Jersey. He grew up attending Pocono Mountain High School in Pennsylvania. There, he became known for being a top scorer on the school's rifle team. During his school years, Frein also joined the Boy Scouts of America and earned the rank of Eagle Scout.

Frein had some jobs while he was growing up. He worked at Lewis' supermarket and later, he attended East Stroudsburg University for one semester. After this, he went to Northampton Community College, where he studied chemistry at two different campuses.

Frein was described as a "self-taught survivalist" by police. Friends mentioned that he held a grudge against law enforcement. Around the time he was part of the Boy Scouts, he experienced rejection from a leader in the council where he worked. This rejection seemed to have a lasting impact on him.

In addition to his academic pursuits, Frein was interested in military simulations. He founded a group named Istočni Vuk, meaning "Eastern Wolf" in Serbo-Croatian. He participated in recreations of military events and even worked in the film industry for a short time, playing minor roles and providing technical advice for documentaries related to war.

Frein lived with his parents in Canadensis, Pennsylvania, at the time of significant events in his life. He had personal interests and hobbies that included shooting and survival techniques, which he pursued in a self-directed manner.

On September 12, 2014, Eric Matthew Frein attacked the Pennsylvania State Police barracks in Blooming Grove. During a shift change late that night, he opened fire with a .308-caliber rifle. He killed Corporal Bryon K. Dickson II and seriously wounded Trooper Alex Douglass.

Three days after the shooting, Frein's vehicle, a 2001 Jeep Cherokee, was found in a swamp near the crime scene. It was partly submerged, and investigators discovered evidence linking Frein to the shooting, including his Social Security card and bullet casings. This led law enforcement to identify him as the main suspect.

A manhunt for Frein began, lasting 48 days. It involved nearly 1,000 officers from various police agencies, including local police, state police, and the FBI. They searched rugged terrain and used tracking dogs, but Frein managed to evade capture. Police believed he was intentionally misleading them and that he enjoyed the challenge of avoiding arrest.

On October 30, 2014, Frein was captured in an open field near an abandoned airport hangar. At the time of his arrest, he was not armed, but authorities recovered a rifle and a pistol from his hiding place. He was taken into custody without struggle and sustained minor injuries during his arrest.

Frein was charged the day after his capture with first-degree murder and attempted murder, among other charges. He pleaded not guilty during his video arraignment. The case garnered much media attention, leading to a jury from another county being brought in for the trial.

On April 19, 2017, Frein was found guilty on all charges. A jury recommended the death penalty, and on April 27, he was formally sentenced to death by lethal injection. He is currently held at SCI Somerset, a medium-security prison in Pennsylvania.