Several people were shot and killed Thursday evening in a Hamburg building used by Jehovah’s Witnesses, police said.

Police spokesman Holger Vehren stated, “We only know that several people died here; several people are wounded, they were taken to hospitals.” The shooting occurred in the Gross Borstel neighborhood of Germany’s second-largest city.

According to him, he doesn’t know how bad the casualties are. The German media had reported six or seven dead, but the police had not confirmed this.

Jehovah’s Witnesses “worldwide grieve for the victims of this traumatic event,” David Semonian, a spokesman based in the United States, said in an email statement to The Associated Press on Friday morning.

Pastoral care is being provided by “the congregation elders in the local area,” he wrote. It has been brought to our attention that the official investigation into this crime is still ongoing. We greatly value the brave assistance of the police and emergency personnel.

The Hamburg police confirmed via Twitter early Friday that they had identified a single shooter and were withdrawing security personnel from the scene.

The police have said that their investigation into the crime’s motivation is ongoing.

They will hold a press conference on Friday afternoon to discuss the situation in greater detail, according to Hamburg’s security officials.

The shooting took place in the Jehovah’s Witnesses’ Kingdom Hall, a modern, boxy three-story building next to a car repair shop.

According to Vehren, the police were called and arrived shortly after 9:15 p.m.

He said that when police arrived, they discovered victims with gunshot wounds on the ground floor, and then heard another gunshot and discovered a dead body on the second floor, which they believe to be the shooter. He insisted that firearms were unnecessary for law enforcement.

According to Vehren, it seemed likely that the shooter was still inside the building or was one of the casualties.

Forensic investigators in white protective suits could be seen moving about the building late at night, continuing their investigation.

Student Laura Bauch, who lives nearby, said “there were about four periods of shooting,” German news agency dpa reported. She claimed that during these times “there were always several shots,” each fired at intervals of about 20 seconds to a minute.

She claimed that she saw someone running up the stairs from the lobby of the Jehovah’s Witnesses building to the second floor.

Gregor Miesbach, a nearby resident, heard gunfire and recorded what appeared to be a person entering the building through a window. Then, sounds of gunfire echo from within. A short time later, the figure is seen in the courtyard before returning to the building and firing more shots inside.

Miesbach reported hearing at least 25 gunshots to the German television news agency NonstopNews. According to him, about five minutes after the police arrived, the final shot was fired.

His footage, published by the Bild newspaper online, showed a man shooting into the building from a first-floor window, knocking out the electricity in the area.

As a light snow fell on Friday morning, investigators could be seen working outside the building to mark evidence by placing yellow cones on the ground and on the windowsills.

At the time of the shooting, police knew nothing about what was going on inside the building. They also lacked any quick clues as to a possible explanation. Background remains “completely unclear,” Vehren said.

Hamburg’s mayor, Peter Tschentscher, called the news “shocking” and extended condolences to the families of the victims in a tweet.

The headquarters of the worldwide organization of Jehovah’s Witnesses can be found in the New York City borough of Warwick, but the religion’s origins can be traced back to the nineteenth century in America. It claims 8.7 million members all over the world, including about 170,000 in Germany.

The group is well-known for its door-to-door evangelism and leaflet distribution in public places. The distinctive practices of this religion include not taking up arms, receiving blood transfusions, saluting the flag of the United States, or participating in secular government.