Information in that regard came to light during interrogation of Brig. Shantha Dissanayake by the CID on May 29, said the official.
Brig. Dissanayake, the security forces commander for the western province at the time of the shooting, was summoned after revelations made by Brig. Deshapriya Gunawardena, who is in remand custody over the incident.
The CID has given another date for Brig. Dissanayake, the immediate superior of Brig. Gunawardena, to report for further interrogation.
The person who had ordered the shooting will be revealed and a key arrest is expected within days, reports say.