An Aetos officer allegedly fired his gun by accident as he was returning the weapon to his company yesterday.

No one was injured in the incident which occurred at about 9.20am at Aetos Security Management's office in West Coast Road.

Police said they are investigating the incident. "An Aetos officer has discharged one round from a firearm at the loading bay," said a police spokesman.

When contacted, an Aetos staff confirmed the incident, but declined to provide more details as police investigations are under way.

According to Shin Min Daily News, the officer is a trainee in his 30s who apparently did not adhere to safety procedures,which resulted in the accidental shot.

The Straits Times understands that Aetos officers are required to remove their firearms from the holsters and have all the bullets removed as a safety measure whenever they return their weapons at the end of their assignments.

A former senior police officer who has spent more than three decades with the Singapore Police Force said that such accidents usually happen when there is a lapse in safety procedures.

"Or it could be a case where the trigger of the gun gets caught on a lanyard," said the former officer, who asked not to be named.

Since 2000, there have been more than 20 cases reported in the media about police or auxiliary police officers firing their weapons.

Four of them involved officers firing by accident and 10 were suicides.

In March 2011, an auxiliary police officer allegedly fired his gun by accident in the staff toilet at Bukit Gombak MRT station.

And in 1999, a Cisco constable was dismissed from service, jailed for a day and fined $250 when he accidentally fired a shot from his revolver while trying to free it after it got stuck in a chair that he was sitting on.

JOYCE LIM