Authorities say they are still hunting for those responsible for a recent spate of attacks involving bricks being thrown at expatriates along the city’s riverfront. Mom Sitha, director of the municipal police department’s foreigners’ bureau, said yesterday that police had not yet identified a suspect, though they believed the perpetrator or perpetrators drove a luxury car. “We did not note the suspects yet, we are still searching for them.” Eight such attacks have been reported to the Post since April, all of them taking place along the riverfront. In each case, an expatriate claims to have been hit by a brick or a piece of rock thrown from an SUV or a truck.