An off-duty Honolulu police officer was involved in an early morning shooting that sent a bar worker to the hospital in serious condition with a stomach wound early Friday.

Police said the gun "accidentally discharged" and were trying to determine whether the fired weapon — a handgun — belonged to the officer.

Deputy Police Chief Dave Kajihiro said at a news conference that both criminal and internal investigations have been started against the 25-year veteran officer, a sergeant who is assigned to the Chinatown district.

Pending the outcome of the Professional Standards Office investigation, the officer faces a possible second-degree criminal assault charge and anything from a written reprimand to expulsion from the police force. The officer’s police powers have been restricted, Kajihiro said.

Kajihiro would not say whether the officer was drinking with fellow officers who were also at the bar in lower Makiki or whether they made the 911 call to report the incident.

Kajihiro said the officer and the 40-year-old female employee of Kings Sports Bar are friends. The bar was not crowded when the shooting occurred just before 2 a.m. at 1283 S. King St.

"There was no struggle. There was no argument," said Kajihiro in explaining what took place.

Kajihiro said police are allowed to carry their firearms even when they are off duty, but are not supposed to do so while under the influence of alcohol. He acknowledged that the police investigation would seek to determine how much alcohol the officer had consumed.

A woman who said she worked in the bar’s kitchen said she believed the shooting was an accident.

A neighbor who lives in a second-floor apartment across the parking lot from the bar said he was awakened "by a loud bang" and screaming by a woman.

There were two accidental shootings involving Honolulu police last year, one fatal.

On Aug. 16, officer Jens Magelssen, 39, was showing his handgun to a friend at his home on Sierra Drive when it accidentally discharged, witnesses said. Magelssen died at the Queen’s Medical Center.

On Sept. 6, an officer accidentally discharged his weapon in the bathroom stall of a department store. No one was injured and no charges were ever filed. Police never released the name of the officer, who has two years of service with HPD. An employee of the store said the bullet went through the wall of the officer’s stall, appeared to ricochet off a door frame and ended up in the wall of an adjacent stall.

Following the department store incident, Kajihiro said all officers had to undergo firearm safety orientation in the use and handling of HPD-issued handguns. That type of refresher training might be required because of Friday’s shooting, Kajihiro added.

Last year HPD’s nearly 2,000 officers were issued Glock 17s —9 mm pistols made with a polymer frame. The Glock replaced the Smith & Wesson 5906, a 9 mm handgun made of stainless steel that HPD officers had relied on as their primary firearm for more than 22 years.

Tenari Ma’afala, the leader of Hawaii’s police union, and high-ranking officers were at the scene of Friday’s shooting.

However, Ma’afala told reporters that he was there not as head of the police officers union but in his official capacity to offer assistance.