Two motorcyclists carried out the shooting and fled the scene.
Investigations so far have revealed that the deceased had had connections with underworld leader Angoda Lokka.
As many as 15 people were murdered in the past two and a half months, mainly over underworld clashes due to drug trafficking rackets and other problems, say police sources.
The killings were reported from Hambantota, Polgahawela, Kotahena, Keselwatte, Sevanagala, Rakwana, Pannala, Grand Pass, Rajagiriya and Athurugiriya.
Meanwhile, shots were fired at a house at Jothipala Mawatha in Athurugiriya at around 3.00 am today.
The house belongs to a private secretary of minister Sujeewa Senasinghe.
No one was harmed in the incident.
Meanwhile, reports say a top police official has received death threats some months ago against investigating the underworld leader Kamburupitiye Madhush, who is in hiding in Dubai.