St Poelten, Austria - Following a month-long family row, a 66-year-old man has shot dead his two siblings and their spouses in Strasshof near Vienna, police said Wednesday. Police said the incident took place on Tuesday in the village of Strasshof, ten kilometres outside Vienna, and was discovered after the man, identified by police as Josef Branis, announced his plan to kill his siblings and himself in a letter to relatives.

Members of Austria's elite Cobra unit then broke down the doors to the homes of the victims early Wednesday morning.

The victims were the man's sister and her husband and his brother and his wife. The four were aged between 56 and 67.

Branis fled after the shootings. After his bicycle was discovered near the Strasshof train station, police suspect he might have fled by train and have issued an international arrest warrant.

Earlier Tuesday, police said he may have already committed suicide as announced in his letter.

Investigations so far have shown that Branis and his siblings have been rowing for 18 months over rent at a flat in Vienna occupied by him

On Monday, he had to leave the flat following an eviction order from his sister.

The village of Strasshof made the headlines in 2006 when Natascha Kampusch managed to escape after being held captive there for eight years by Wolfgang Priklopil.