The suspects held up the bus with the driver and two passengers who were travelling to work.
Fortunately, Police chief inspector David Terry was passing through when he happened on the scene.
“This incident happened as we were passing them near the Morata vocational centre,” Terry posted on his Facebook page.
“I was going to drop my nephew at Morata Three when the criminals struck.
“My friend who was driving my vehicle stopped in the middle of the road when we saw the thugs attacking the victims inside the bus.
“We heard a loud sound when the suspects landed a rock on the windscreen. I got out only to find myself staring at the driver and the gunman scuffling.
“I drew my weapon and as the suspect fled with the wallet, I aimed at his hinds and fired.
“The suspect kept running while I quickly returned to the offside position only to see four others fleeing at the sound of gunfire.
“I discharged two more shots aimed at their legs as they fled into the darkness.
“The driver and two other employees were in a state of shock as I comforted them and told them to report to Waigani police.
“I am now appealing to Morata residents to report to Waigani Police Station anyone who has sustained fresh bullet wounds.
“Please contact me on 322 6243 if you know something about this crime.”