Police in Thessaloniki yesterday were seeking the perpetrators behind three bomb attacks, two on unionists and one on the home of a policeman, none of which caused injuries. A homemade explosive device planted outside the eighth-floor apartment of Sotiris Zarianopoulos, the general secretary of a local labor union, near the city center, detonated shortly before 2 a.m. At around the same time, a similar device went off outside the home of a policeman in the district of Ambelokipi. Shortly after 11 a.m. another homemade bomb went off outside the home of a former unionist in central Thessaloniki. The target of the attack was Dimitris Gousidis, the former head of the union representing journalists in Macedonia and Thrace. All three attacks caused limited damage but led to no injuries.