Opportunistic petrol thieves may have lost their appetite for crime after seemingly copping a taste of raw sewage in a botched siphoning attempt.

Laverton Police Sen. Sgt Heath Soutar said a visiting tour bus fell victim to an attempted theft last week.

Sen. Sgt Soutar said it appeared the would-be thief or thieves tried to siphon fuel from the parked bus during the night.

However, they got a bit more than they bargained for when they accidentally accessed the bus’ waste tank instead of the one containing fuel.

Sen. Sgt Soutar said the discarded cap and lack of fuel stolen suggested they had failed to get away with what they were hoping to steal.

“We can infer they beat a very hasty retreat, with a somewhat bitter taste in their mouth, ” he said.

Sen. Sgt Soutar said that while Laverton Police were looking for the offenders, police officers “have absolutely zero interest” in tracking down the stolen goods.

He did however say officers were hoping “word of mouth” would help crack the case.