Church volunteers spent Monday cleaning up after the chaos that followed a fatal shooting during Sunday Mass, Local 4 reported.

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Victim's Brother Reacts To Church Shooting

The local archdiocese told the station that the worship space at St. Paul's Albanian Catholic Church in Rochester Hills has been desecrated, and a special service called a ceremony of repentance will be required.

The statement follows the death of Gjek Isufaj, 38, of Madison Heights, who was reportedly shot several times in the back of the head by Gjon Pepaj, 38, of Rochester Hills, during Sunday's service.

Several other people were injured trying to flee the building, authorities said.

Police say many inside the church thought it was an act of terrorism, causing panic among the crowd.

Oakland County Sheriff Michael Bouchard said Pepaj apparently approached Isufaj (pictured, left) from behind and shot him from about three or four feet away.

Pepaj was taken into custody following the shooting, Bouchard said.

Isufaj's family told Local 4 they were shocked that someone would do such a cowardly act in front of over 1,000 parishioners, Local 4 reported.

Authorities, who were dispatched to the church about 1:11 p.m., recovered two handguns and there were several casings found on the ground.

Bouchard said neither the victim -- who was at Sunday's service with his son and daughter -- nor the suspect were members of St. Paul's. The children are between ages 10 and 15, Bouchard said.

Parishioner Luigi Gjokaj, 42, said the priest was preparing to distribute the sacrament of Eucharist when the suspect stood up and yelled "yes, I am here" before shooting the victim.

Witnesses said the gunman then fired into the air, and yelled, "I done what I was supposed to do."

Family members of the victim believe Pepaj's actions were the result of a dispute that happened eight years ago.

Authorities say Pepaj may have acted out of fear that someone would harm his family, Local 4 reported.

The two men had reportedly been good friends -- Pepaj was the best man at Isufaj's wedding.

In a church statement Sunday, the Rev. Anton Kqira called the shooting "the result of a dispute between individuals."

"Our prayers and condolences go out to the family of the victim," Kqira said.

Bouchard said at least seven other churchgoers were treated for minor injuries on the scene and at least four were being transported to area hospitals.

Bouchard said most of the injuries -- primarily cuts and bruises -- appear to have been sustained when people tried to flee. He said some jumped through windows to escape the shooting.

The church plans to hold its repentance ceremony later this week.