After taking keys from a drunken guard who'd fallen asleep, a group of 31 men escaped police holding cells in Papua New Guinea's Lae.
The National newspaper reported police superintendent Chris Kunyanban saying the guard had fallen asleep at his post after "consuming alcohol with juvenile prisoners in the watch house".
The prisoners took the keys from his pocket and opened cell doors early on Wednesday morning.
Police were alerted to the prison break at about 6.30AM and quickly recaptured four of the men, Kunyanban said.
Twenty seven are still at large, 15 of whom are charged with serious offences.
The sleeping guard has been suspended pending an investigation.
"The investigation will also look at the system in place, security protocols and standard operating procedures."
Kunyanban said the holding cells had a capacity of 100 prisoners but were holding more than 140 at the time of the escape.
The superintendent drew attention to overcrowding at the cells last month, when Loop PNG reported the escape of an undisclosed number of prisoners from the same facility.
A hole was cut in the outer fence while the prisoners were taken outside to shower.
Meanwhile, police are yet to capture 33 men who escaped from Lae's Buimo prison last month, the sixth breakout from Buimo since 2015.
"It is becoming very hard. But we are relying on public assistance," Kunyanban said.