The tunnel had a diameter of 50 x 75 centimeters and was found filled with water on Monday morning, Widjaja said.
Kerobokan houses a fairly large number of foreign inmates, given Bali’s status as an international holiday destination and transport hub.
The four men were serving sentences for different crimes, from immigration rules violation to drug crimes, Widjaja said.
The remaining jail time for 33-year-old Australian Davidson, who was sentenced to a year in prison for breaking immigration laws, was two months and 15 days, while 31-year-old Indian Said had 12 years and three months to serve for drug offenses.
The head of the prison said that 10 guards were on duty on Sunday night when the escape is believed to have taken place.
Indonesian prisons are frequently overcrowded and a war on drugs being led by the government of President Joko “Jokowi” Widodo has triggered a spike in the number of convicted drug offenders, stretching an already overwhelmed jail system.
The capacity of Kerobakan is 323 inmates, but it currently houses more than four times that number at 1,378, according to government data.
Prison escapes are fairly common in Indonesia and authorities launched an investigation last month after around 350 inmates broke out of an overcrowded jail in Riau.
Courtesy of Jakarta Globe