They escaped by breaking open a window in their cell and making a hole in the wall in front of the official quarters of prison superintendent Samantha Alahakoon and the chief jailer.
That area had been left unguarded for around a week.
Alahakoon assumed duties around a fortnight ago, and he has been appointed to the position due to reported mediation by the prisons commissioner general.
The escaped prisoners include Rasaiah Jayakumar of Nawalapitiya, who is accused of having murdered the wife of a leading businessman at Medemulla in Minuwangoda in March 2015.
The others are Ansar Mohamed of Jaffna, Vipula Prasanna of Wattala and Chatura Madhusanka of Kurunegala.