Twenty-seven-year-old Jacob Schmoyer mailed a series of letters to his family and the Allentown Police Department indicating his intentions, ATF Philadelphia Field Division Special Agent in Charge Don Robinson told reporters during a Thursday morning press conference.
"It is the collective opinion and assessment of the entire investigative team that this was an intentional act. It was a murder-suicide, an intentional act by Jacob Schmoyer," Robinson said.
The explosion occurred around 9:30 p.m. Saturday night in the 700 block of Turner Street. The blast killed Schmoyer, his 2-year-old son Jonathan "J.J." Schmoyer, and 66-year-old David Hallman.
Authorities worked to piece together Schmoyer's destroyed vehicle and deduced where the explosive device was placed when it ignited. They believe it was located on the center console of the car.
Robinson said all three were inside the vehicle at the time, with the toddler in a car seat in the back. He said there is no further risk to the public.
"We are confident Schmoyer acted alone. He is not involved in any groups. We are confident that this was an isolated incident, a criminal act by Jacob Schmoyer," Robinson said.
Authorities say they were able to confirm that Schmoyer used homemade explosives in the device using evidence at the scene and the letters he sent.
Robinson said the one letter sent to the Allentown Police Department was "very specific as far as the components, and the materials used, the construction of the explosive device."
Authorities still have to confirm the letters' authenticity, but are very confident they were sent by Schmoyer.
"All of the letters indicated that Mr. Schmoyer was to blame. He took blame for it," Robinson said.
The first two letters indicated he intended to target his associate, David Hallman, officials say. Another letter indicated he intended to take his son with him.
Schmoyer admitted to petty thefts and burglaries in the letters and spoke about himself in negative terms, officials say.
"He was miserable. The four letters describe a miserable life. He was unhappy with himself," Robinson said.
Allentown police say the streets around the scene have reopened.
Though officials believe they have found all pieces of evidence involved in the explosion, they are asking anyone who finds something that might be connected to call them.
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