A family of three, including a 12-year-old boy, was killed Friday in the northern city of Thessaloniki, police said.
The suspect attempted suicide and has been detained, Xinhua reported citing police.
Police said the 60-year-old man, who entered the family's house armed with a gun and a knife, had an argument over financial transactions with the father, who was also the suspect's brother-in-law.
Investigators believe that the suspect shot all the victims at close range before jumping off the balcony to commit suicide.
The suspect has been transferred to a local hospital.
