Police arrested the gunman wanted in connection with the murder of Public Health Inspector (PHI) Deepal Roshan Kumara in Elpitiya.
The arrest, made in Mount Lavinia, also led to the recovery of two firearms from the suspect.
PHI officer Deepal Roshan Kumara, attached to the Karandeniya PHI office, was fatally shot in Divithurugama, Elpitiya, on February 26 of this year.
Earlier, another suspect linked to the murder was arrested at Katunayake Airport while attempting to flee to Dubai using a counterfeit passport.