Shaun Edward Davidson, right, going into a holding cell after being sentenced to a year's jail minus time served in September last year. Credit:Amilia Rosa Mr Pasaribu said under Indonesian law the men would not receive extra jail time for escaping if they were recaptured. "Maybe we should change the law," he said. "If they damaged property during their escape they will be separately tried for that. If anyone assisted them they would also get prison time." Mr Pasaribu said he had no idea why Davidson had escaped when he only had 10 weeks of his sentence left to serve."Hopefully we can catch them soon so we can find out the reason why." He urged anyone who saw the escapees to report them to police. Prison governor Tonny Nainggolan admitted authorities never suspected the cement cover near the jail's clinic disguised an escape tunnel.

Photos of the missing prisoners, including Shaun Davidson on the right. Credit:Amilia Rosa "We assumed it was the top of the septic tank because it was located next to the clinic toilet," he said. "It's been there for a while. We didn't suspect anything, because if they dug up a new tunnel, where would they hide the dirt from the digging? There was none." The men - who were all from Block B - were in lockdown at the time of the daring escape. Authorities comb the area where the escape is believed to have taken place. Credit:Amilia Rosa It is believed they escaped through a hole in the ceiling of their block and then squeezed through the waste tunnel, which was 13 metres long and just half a metre wide.

Fairfax Media overheard an investigating police officer mutter: "The distance was 13 metres? Who could hold their breath that long?" The exterior wall of Kerobokan prison, which houses more than 1300 inmates. Credit:Amilia Rosa The tunnel was drained on Monday morning "for humanitarian reasons" in case the prisoners were still stuck inside. Mr Tonny said prison authorities believed the escape had been planned for some time. The tunnel through which the Kerobokan inmates escaped.

"Shaun started growing a beard and moustache, we suspect to change his appearance," he said. Two buckets, some towels and sandals were found near the tunnel entrance. Shaun Davidson waiting to be transferred to Kerobokan jail in Bali after being charged with possessing another person's identity and overstaying his visa in April last year. Credit:Amilia Rosa Mr Tonny said there were more than 1300 prisoners in the notoriously overcrowded jail. He said Tower Two, which was above the tunnel exit, had been empty at the time of the escape because of a shortage of guards.

Australian man Shaun Davidson is still on the run. Credit:The Age "We only have 10 guards each shift," he said. Of the 10, one was posted to each corner tower, four were rotated on the ground and there was one commander and an assistant. "We have requested 200 extra officers but so far it has not been approved," he said. A source at Kerobokan jail told Fairfax Media the foreigners had last been seen at sahur - the term for the predawn meal before fasting begins during Ramadan. "They are still investigating whether they escaped through the waste ground tunnel behind the clinic. It is filled with water," the source said.

The escapees, whose families had all been notified, also included a Bulgarian, an Indian and a Malaysian. Bulgarian Dimitar Nikolov Iliev was jailed for seven years for money laundering, Indian Sayed Mohammad Said was jailed for 14 years on drug charges and Malaysian Tee Kok King was jailed for seven years on drug charges. The prison governor, Mr Tonny, said the four prisoners had been just like any other. "Their behaviour was normal. (Davidson) teaches boxing. The Indian guy was quite religious but he didn't mingle a lot." Sayed Mohammad Said was last seen by another prisoner during morning prayers and again at 6.30am this morning. Davidson was jailed for a year last September after he was found guilty of misusing a travel document belonging to someone else.

He had been due to face Perth Magistrates Court on January 28, 2015, charged with possessing methamphetamine and cannabis and two other offences. When he did not attend, an arrest warrant was issued. But instead of going to court, Davidson skipped the country, arriving in Indonesia in 2015 on a one-month tourist visa Davidson said he lost his passport. He said he had contacted the Australian passport office and reported his own missing, but then began using a passport under the name of Michael John Bayman, which Davidson said he had found in a hotel room. Bali immigration authorities told Fairfax Media the passport had been reported missing by its real owner in 2013.

In an interview with Fairfax Media between the bars of a holding cell at Denpasar District Court last September, Davidson said the conditions in Kerobokan were bearable if one had money and support from the outside. He said he had been expecting a "living hell" when he was incarcerated in April last year after being named a suspect. Davidson told Fairfax Media at the time that he would continue to teach boxing inside Kerobokan jail. "I have about 15 to 20 people I train in boxing, so that's pretty good. I guess it gives the locals something to do. It gives them something to look forward to. It's pretty hard for some of the locals - if you don't have money to get food you don't eat." Davidson had spent the year before he was apprehended boxing and partying in Bali.

But he came to the attention of authorities in March last year when he was staying at Rabasta Hotel in Kuta. Ngurah Rai airport immigration officer Mohamad Soleh told Fairfax Media in April last year that a report was made of a foreigner staying in Kuta who was suspected of overstaying his visa. When immigration authorities investigated, they found he had not only overstayed but was using a fake identity. The vice-director of Special Criminal Investigation, Ruddi Setiawan, said on Monday police were cooperating with immigration and justice officers to search for the escapees. "We are investigating witnesses," he said.

Mr Setiawan said they were also investigating the possibility they escaped via the waste tunnel. "If so, by the estimated time of escape, the street would have been crowded with traffic." Loading He said there was a possibility someone from the outside helped them with the escape, as they would have emerged dirty and wet. Follow Jewel Topsfield on Facebook