He is commenting on medical reports that a schoolboy and father of one who had been arrested over the murder of the girl Seya Sadevmi, had been beaten up by police.
Torture by police to extract information should be stopped, he said.
Police should be given training on new methods in crime investigation, said Dissanayake.
He noted that since Sri Lanka in 1994 signed the charter against torture, it is an offence punishable by law to torture anyone.