A Serbian man on Tuesday shot dead thirteen relatives and neighbours, including a two-year-old child, as he went on a pre-dawn killing spree in his tiny village in the Belgrade region, police said.
It was the worst such incident in the Balkan country in two decades.
The 60-year-old war veteran, identified as Ljubisa Bogdanovic, shot most of his victims in the head as they slept before trying to kill himself and his wife.
Both were seriously wounded along with a third person, who later died in a hospital, Serbian police chief Milorad Veljovic told reporters at the scene labeling the crime "monstrous."
He said the victims who died -- six men, six women and the child -- include Bogdanovic's mother and his 42-year-old son.
"Twelve people were killed on the spot while the 13th died in hospital," said Veljovic.
According to the victims' neighbours the killed child was a boy, whose name was David, while most of the victims were Bogdanovic's relatives.
The motive for the attack in the village of Velika Ivanca, located about 50 kilometers (30 miles) south of Belgrade, was not immediately clear.
Veljovic said Bogdanovic went house to house at 5:00 am local time (0300 GMT) methodically shooting his victims in five houses located on a hill on the outskirts of the village.
He is thought to have first killed his son and mother, then wounded his wife, before continuing on his spree and turning the gun on himself when a police patrol arrived.
"When he saw the patrol he shot himself in the head in a yard," an interior ministry statement said.
Residents of the village of about 1,700 inhabitants were in shock Tuesday and some wept as they tried to understand the reason behind the killings.
Neighbours said Bogdanovic, who fought as a Serb soldier during the 1990s war in Croatia and had a firearms license, lost his job as a labourer last year. He then became a farmer.
"I talked to him yesterday. I asked him how he was, and he said fine. He asked me about my health," Stanica Kostadinovic, a visibly shocked neighbour in her 60s, told AFP.
"He was the best neighbour. Nothing indicated that such a thing could happen.
"He was a good host, he and his son, nice, hard-working, always ready to help," she added.
Police on Tuesday sealed off access to the five houses where the killings took place and prepared to remove the victims' bodies.
Kostadinovic's husband Milovan said Bogdanovic's father had committed suicide when he was a child.
"He grew up without a father," Kostadinovic said, adding that some of Bogdanovic's family members had undergone psychiatric treatment in the past.
The killer's brother Radmilo Bogdanovic, whose house sits on a hill facing the crime scene, insisted that "nothing could have have hinted to this tragedy".
"I ask myself only one thing: why, why he has done this? How could he do it, how?!" the 62-year-old told AFP, sobbing in the garden of his yellow-brick house strewn with children's toys.
"He was a picture of honesty, as a child he was fearful... I don't understand what has happened to him... He was a normal man, something must have broken him ... the whole village is shocked."
Bogdanovic, his eyes red from crying, remembered that his brother was affected by the events of the 1991-1995 war in Croatia in which he took part.
"Whenever I raised the issue, he would always reply 'May God save you from living what we went through'."
In a similar attack in 2007, a gunman killed nine people and wounded two in the village of Jabukovac, in eastern Serbia.