A Pennsylvania man who opened gun fire on, and killed, another worshipper in front of a packed congregation on April 23 at a Montgomery County church was since charged with manslaughter. The shooter faces a prison sentence of up to two decades. Storms will be arraigned Thursday afternoon.

Mark Storms, 46, of Lansdale, Penn., was charged Thursday with voluntary manslaughter and reckless endangerment in the death of 27-year-old Robert E. Braxton III, reports NBC News in Philadelphia.

Storms shot Braxton inside Keystone Fellowship Church, a non-denominational church, prosecutors said. The shooting happened in the church's sanctuary, which was filled with hundreds of worshippers for an 11 a.m. service. Witnesses said churchgoers hid under pews as the altercation occurred.

Witnesses stated Braxton arrived at church irritated, and cursed at an usher in the back of the church, court documents show. Church staff members tried to quiet Braxton, but he refused before heading to a pew reserved for two other church members, according to prosecutors.

A church member sitting behind Braxton tapped him on the shoulder to let him know the seats were reserved. Another couple put down two Bibles to save their spots before walking away. Braxton retorted the tap and starting yelling "Don't (curse word) touch me!" an affidavit reads.

Witnesses told police that Storms walked over to Braxton, showed him a badge and motioned to a handgun under his shirt. The badge, police said, was for his concealed carry permit. Braxton exchanged words with Storms before punching him in the jaw. Storms then pulled out his gun and fired two shots, according to witnesses.

Church members told police varied, various pieces of what occurred between Storms showing the badge and the shooting. One person said Braxton lunged at Storms before the shooting. Another recalled hearing Braxton ask Storms:  "What are you going to do, shoot me?" before punching him, court documents show.

Storms, in an interview with police, said he opened fire on Braxton because he felt his "person was in great danger" and that he was worried other people in the church, including the elderly and children, were going to be hurt.

Storms also told police he showed off the concealed carry badge with hopes of defusing the situation. He said, according to court documents, he had done that in the past and that men "walked away."

Following the shooting, Braxton was taken to Abington-Lansdale Hospital where he died, reports NBC. An autopsy showed a bullet hit him in the right side of his chest and right arm.

Kevin Steele, Montgomery County district attorney, said his office decided to file charges after an intensive investigation and interviews with 50 witnesses.