A Denver police officer accidentally fired his gun while trying to turn on a flashlight mounted on his weapon in March, the department’s third flashlight-related discharge in two years, records show.

Denver officials last month suspended Officer Brian Mudloff for 18 days without pay for careless handling of his firearm in connection with the March 16 discharge. The Denver Post obtained Mudloff’s discipline order this week through an open-records request.

Nobody was seriously injured, but the bullet went through a car’s windshield and through the front passenger seat, shattering a rear side window.

Inside the car were the driver, a juvenile passenger, an infant and a theft suspect.

The revelation follows a report this year by The Post highlighting accidental shootings by police officers with gun-mounted flashlights.

A national review by the newspaper found that in the past nine years, five people were shot accidentally in such incidents.

The March shooting was the third accidental discharge because of gun-mounted flashlights documented by the Denver Police Department.

Manufacturers of the flashlights defend their use, saying accidental discharges are extremely rare and the lights benefit officers who use them properly.

But Denver Police Chief Robert White grew so concerned about the use of the lights that last year he banned tactical flashlights with switches below the trigger guard. This year, he required additional training for officers using approved flashlight models.

Some police firearms experts recommend going farther and banning all gun-mounted flashlights. Gene Maloney, a retired master firearms instructor with the New York Police Department, said the risk outweighs the benefits.

“If you put a flashlight on a gun, the gun becomes something other than a gun,” Maloney said. “A firearm should be a firearm. We were concerned in New York that if you put a flashlight on a gun, the police would start using the gun as a flashlight. When you do that, you point a loaded firearm in an area not intended for shooting.”

Adding switches to a loaded firearm isn’t advisable, he added, especially considering the “loss in fine motor skills during stressful situations.”

Other experts defend the use of gun-mounted flashlights while cautioning that proper training is crucial.

White does not plan additional changes to policy, said Ron Hackett, a spokesperson for the police department. Officer Mudloff did not return telephone messages seeking comment.

Mudloff was using an approved flashlight.

White said earlier this year he did not think the March incident was related to flashlight issues. The recent discipline order, signed by Deputy Director of Safety Jess Vigil, shows the flashlight was a factor.

Vigil stated that Mudloff and his partner responded to reports of a stolen vehicle in west Denver the night of the shooting.

Mudloff, who was in the passenger seat of the squad car, drew his handgun as he moved to get out of the vehicle. As he did so, he tried to activate his gun-mounted flashlight, which has switches just to the front of and almost parallel to the gun’s trigger, according to Vigil’s account.

Vigil said Mudloff attempted to activate the flashlight using his right index finger, which is his trigger finger. Training required him to use the thumb of his hand, which would not be used to pull the trigger of the gun, according to Vigil.

Mudloff’s trigger finger was on the flashlight switch as he exited, Vigil recounted. When the passenger side door of the police car unexpectedly swung back and struck Mudloff, he was knocked off balance, which caused him to unintentionally pull the trigger on his handgun, Vigil said.

The accidental discharge “placed several individuals at great risk of serious bodily injury or death,” Vigil said. The only injury was slight. The driver received minor injuries from flying glass.

The Denver Post tried to contact the people in the car but was unsuccessful Thursday.

In Denver, the first accidental flashlight-related discharge occurred in January 2013. No one was injured in that incident, which occurred when an officer searched for an armed suspect in a homeless camp. The officer meant to activate his flashlight but pulled the trigger instead as he pulled open a tent flap. One bullet was fired into the empty tent.

In the second case, seven months later, the officer might have shot someone. He pulled over a suspected stolen vehicle and went to shine his gun-mounted flashlight inside. The suspect drove off. The officer stumbled, firing his gun as his finger slipped onto the gun’s trigger.

After the stolen car was found, “there was a small amount of blood on the driver’s seat and center console,” according to a report from Denver’s independent monitor, Nicholas Mitchell, who reviews the discipline of Denver police.

Christopher N. Osher: 303-954-1747, cosher@denverpost.com or twitter.com/chrisosher