DENPASAR, Indonesia (Reuters) - Indonesian police have launched a search for four foreign inmates, who escaped from an overcrowded prison on the resort island of Bali by crawling through a narrow tunnel dug under the walls, authorities said on Monday. 
 
 “The tunnel is about 12 meters (39 ft) long and we suspect it took more than a week to build,” the head of Kerobokan prison Tony Nainggolan said, adding that police believed the men were still in Bali and not far from the prison. 
 
 The four are Australian Shaun Edward Davidson, Bulgarian Dimitar Nikolov Iliev, Indian Sayed Muhammad Said and Malaysian Tee Kok King, Bali police spokesman Hengky Widjaja said. 
 
 The tunnel had a diameter of 50 x 75 cm (20 x 30 inches) 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 2 months and 15 days, while 31-year-old Indian Said had 12 years and 3 months to serve for drug offences. 
 
 The head of the prison said that 10 guards were on duty on Sunday night when the escape is believed to have taken place. 
 
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 Indonesian prisons are frequently overcrowded and a war on drugs being led by the government of President Joko 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 on Sumatra island in Riau Province. 

 Media playback is unsupported on your device Media caption A hole found in the outer wall connected to the tunnel 
 
 Indonesian police are searching for four foreigners who escaped from Bali's Kerobokan Prison using a tunnel. 
 
 The prisoners were identified as Australian Shaun Edward Davidson, Bulgarian Dimitar Nikolov, Indian Sayed Muhammad and Malaysian Tee Kok King. 
 
 Prison governor Tony Nainggolan said he believed the men were still on the resort island. 
 
 Prisons in Indonesia are dealing with an influx of people arrested for drug offences, and breakouts are common. 
 
 The four men were serving jail terms for a mix of drug and fraud offences. 
 
 They are believed to have escaped through a 50cm by 70cm hole found in the outer wall which connects to a 12m-long (36-foot) narrow tunnel, officials said. 
 
 Some reports said it was an existing tunnel used for water drainage. 
 
 Image copyright ABC 
 
 Staff noticed they were missing on Monday morning during a routine check. 
 
 Australian Shaun Davidson had less than three months left of his sentence to serve, according to the jail governor. 
 
 About 200 prisoners broke out of an overcrowded jail on Sumatra island in May after being let out of cells for Friday prayers. 
 
 Inmates had accused some guards of being violent and complained about their treatment in jail.
– Police in Indonesia are hunting for four foreigners who tunneled out of a prison in Bali, the BBC reports. The men escaped from Kerobokan Prison by crawling through a 39-foot-long tunnel dug under the walls, per Reuters. The prison chief says "we suspect it took more than a week to build" the 20-by-30-inch escape route. It was found filled with water on Monday morning. The inmates are believed to still be on the Indonesian resort island. Kerobokan houses 1,379 inmates, four times the official capacity, many of them foreigners. The men were serving sentences for drug, fraud, and immigration offenses, per Reuters. Australian escapee Shaun Edward Davidson, 33, had only two and a half months left to serve. The other men hailed from Bulgaria, India, and Malaysia. (Indonesia considered a prison guarded by crocodiles.)