Father killed self, son, friend in Allentown car explosion, blast ruled murder, suicide

3 Men Killed in Pennsylvania Car Explosion, ATF Investigating

Three people were killed in a fiery car explosion in Allentown Saturday night.

Update 11:48 a.m. EDT Oct. 4: Police in Pennsylvania have ruled the deadly car explosion in Allentown over the weekend as a murder/suicide.

Jacob Schmoyer killed himself a along with his 2-year-old son Jonathan, or "J.J.," and a friend, 66-year-old David Hillman, The Associated Press reported.

Investigators with the Bureau of Alcohol, Tobacco, Firearms and Explosives, said that Schmoyer sent letters to family and police, telling them of his plans to use explosives to kill himself and his friend and son, the AP reported.

Police are calling it an isolated incident, WFMZ reported.

Original report: Pennsylvania authorities are investigating a fiery car explosion in Allentown Saturday night that killed three and closed down several streets in what police are calling a "criminal incident," according to news reports.

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The FBI and agents with the Bureau of Alcohol, Tobacco, Firearms and Explosives are also involved in the investigation.

Residents were ordered to shelter in place, according to WPVI-TV.

In a news conference Sunday, authorities told reporters they believe the explosion was an isolated incident and that there is no continuing public threat, WPVI reported.

"We know there's been a criminal incident," District Attorney James Martin said during a news conference Sunday, according to The Associated Press. "We have a high degree of confidence that the perpetrator was probably killed in the incident," he said.

Autopsies on the three victims are scheduled for Monday. The identities of the victims have not been released.

It’s unclear if the victims were in the car or bystanders.