FORT LAUDERDALE, Fla. -

Broward Sheriff's Office said Friday that they had taken over the investigation of a fatal shooting involving a veteran Fort Lauderdale police officer.

The Thursday night shooting left 40-year-old Richard Arruda dead and Fort Lauderdale police officer Mark Shotwell badly injured.

Shotwell was not on duty when he exchanged fire with a man at the parking lot of the Maguires Hill 16 at 535 N. Andrews Ave.

"This is a service that the Broward Sheriff's Office provides any agency that has an incident involving one of their own officers," Fort Lauderdale spokeswoman Deanna Greenlaw said.

Fort Lauderdale Capt. Frank Sousa said the homicide investigation was "a difficult moment" for the police department.

Police interviewed witnesses. Local 10 News Liane Morejon was at the scene of the shooting early Friday morning.

"I heard it, about seven shots -- three from one gun and four from another," said witness Fred Gans, who added that at first he confused the noise with fireworks.

Around 7:30 p.m. Thursday, Arruda and his girlfriend, Christine Menatti, pulled into the parking lot of Maguires Hill 16 after getting into a physical confrontation inside a vehicle, deputies said Friday evening.

Police investigate fatal shooting at Ft. Lauderdale restaurant

OFFICER IS RECOVERING AFTER HE WAS INVOLVED IN A DEADLY SHOOT OUTSIDE OF A REST SHOOT OUTSIDE OF A RESTAURANT. THE OFFICER IS VETERAN DETECTIVE MARK SHOTWELL. HE AND ANOTHER PERSON WERE SHOT IN WHAT WAS A FIGHT OUTSIDE OF MAGUIRE HILL RESTAURANT NUMBER 16 ON NORTH ANDERS AVENUE IN FT. LAUDERDALE. WE BEGIN OUR TEAM COVERAGE RIGHT NOW WITH LOCAL 10 NEWS REPORTER LIANE MOREJON. I HEARD SEVEN SHOTS, FOUR FROM ONE GUN AND THREE FROM ANOTHER. Reporter: THE WITNESSES WERE QUESTIONED OVERNIGHT BY DETECTIVES FROM THE SMOVS. FIRST I THOUGHT IT WAS FIREWORKS, BUT THE SECOND GUN MADE DIFFERENT NOISE. Reporter: SOME OF THE 50 PEOPLE INSIDE MAGUIRE PUB WHEN A GUNFIGHT ERUPTED IN THE PARKING LOT. THIS MORNING INVESTIGATORS WERE STILL AT THE SCENE. EVIDENCE MARKERS AND BLOOD SPLATTER STILL ON THE GROUND. THE CALL CAME IN AROUND 7:30 LAST NIGHT. A MAN AND WOMAN WERE ARGUING INSIDE A CAR THAT PULLED INTO THE PARKING LOT OF MAGUIRE PUB. ONE OF THE WAITRESSES WAS IN A DOMESTIC DISPUTE WITH HER BOYFRIEND. Reporter: AT THAT TIME THE OFFICER CAME OUTSIDE AND NOTICED THE COUPLE FIGHTING. HE AND ANOTHER FRIEND OF MINE WAS ON THEIR WAY WITHOUT. Reporter: SOMEONE OPEN FIRED. A GUN BATTLE BETWEEN THAT SUBJECT AND AN OFF-DUTY FT. LAUDERDALE POLICE OFFICER. TRYING TO BREAK UP A DOMESTIC FIGHT. I DON'T THINK HE SAW IT COMING. Reporter: THE SMOKE CLEARED AND THE MAN WAS DEAD AND THE OFFICER WAS HIT. HE WAS RUSHED TO BROWARD MEDICAL CENTER AND TAKEN INTO SURGERY. HE IS A MEMBER OF OUR AGENCY. HE IS A MEMBER OF OUR FAMILY. A DIFFICULT MOMENT FOR US. A DIFFICULT MOMENT FOR INVESTIGATORS. Reporter: THE BUSTLING BAR POPULAR WITH COPS AND PROSECUTORS NOW A CRIME SCENE, DETECTIVES GATHERING EVERY POSSIBLE CLUE TO FIGURE OUT EXACTLY WHAT HAPPENED OUR CRIME SCENE IS INVESTIGATING NOW TAKING PICTURES, GATHERING EVIDENCE. LIANE MOREJON REPORTING FOR US.

Shotwell had just left the restaurant to go home when he came upon the altercation between Arruda and Menatti. Menatti, who works at Maguires and recognized Shotwell, asked him for help, alleging Arruda had battered her, according to the Broward Sheriff's Office.

Deputies said Arruda got out of the vehicle and shot Shotwell, who managed to reach for his weapon and returned the gunfire, fatally shooting Arruda.

Fort Lauderdale Fire Rescue took the veteran officer to a nearby hospital where he remains in critical condition but is stable. Deputies said Fort Lauderdale Fire Rescue pronounced Arruda dead at the scene.

"One of the waitresses here was on a domestic dispute with her boyfriend," witness John Kluge said.

More than 40 people remained inside the business while BSO crime scene and homicide detectives collected evidence from the parking lot, deputies said.

Local 10 News John Turchin reported Shotwell was in critical but stable condition at Broward Health in Fort Lauderdale Friday.