Eight people were killed and 14 wounded in Serbia’s second mass shooting in two days and a suspect was arrested, authorities said on Friday, causing horror in a nation that had just started three days of mourning for victims of the first shootings.

The latest incident occurred late on Thursday in the village of Dubona, 42km (26 miles) south of Belgrade, authorities said.

State broadcaster RTS said the suspect, a young man, had been involved in an altercation in a schoolyard. He left and then returned with an assault rifle and a handgun, opened fire and continued to shoot at people at random from a moving car.

“The suspect U.B., born in 2002, has been apprehended in the vicinity of the city of Kragujevac, he is suspected of killing eight people and wounding 14 overnight,” Serbia’s Interior Ministry said in a statement. An investigation was ongoing.

An off-duty policeman and his sister were among those killed, RTS reported.

“This is sad, the young policeman is my daughter’s age, born in 1998,” said Danijela, a middle-aged woman in Dubona. “My daughter is taking sedatives, we could not sleep all night. They grew up together.”

Police used a helicopter, drones and multiple police patrols to hunt down the suspect.

‘A huge defeat’

“This is terrible for our country, this is a huge defeat. In two days so many … killed,” said Ivan, a Dubona resident.

Serbs were still reeling from a mass shooting on Wednesday when a 13-year-old boy shot dead nine and injured seven at a school in Belgrade before turning himself in.

Serbian President Aleksandar Vucic was scheduled to address the nation around 10:30am (0830 GMT) on Friday.

Around 600 Serbian police, including the elite Special Anti-terrorist Unit (SAJ) and Gendarmerie were involved in the hunt for the suspect overnight in what was dubbed Operation Whirlwind, RTS reported.

Heavily armed police set up a checkpoint in the village of Dubona overnight and searched incoming traffic. Armoured police SUVs and black vans circled the area.

The wounded have been transported to several local hospitals and the Health Ministry has appealed to people to donate blood, RTS reported.

Serbia has an entrenched gun culture, especially in rural areas, but also strict gun control laws. Automatic weapons are illegal and over the years authorities have offered several amnesties to those who surrender them.

The Balkan nation began three days of official mourning on Friday for the victims of Wednesday’s mass shooting.

The suspected shooter in that incident took two of his father’s handguns to kill eight pupils and a security guard in a hallway and history class at their school in Belgrade.

Hundreds of school children with candles and flowers had gathered for a vigil on Thursday evening in streets around the school, while churches planned memorial prayers.

Dozens of high school teachers rallied in front of the Education Ministry in downtown Belgrade on Thursday, demanding improvements to school security and the education system.

After Wednesday’s shootings, the government introduced a two-year ban on the issuing of new gun permits, a revision of existing permits and checks on how gun owners store their arms.

Still, Serbia and the rest of the Western Balkans remain awash with military-grade weapons and ordnance that remained in private hands after the wars of the 1990s.