A day of violence that started with a gun battle that injured eight - including one of the possible shooters - continued throughout Saturday along a mile stretch of Blue Hill Avenue, from Talbot Avenue to Supple Road, even as police worked to keep Carnival goers safe.

The Boston Police Department reports arresting three men and a teenager after a gun battle on Talbot Avenue just steps from the J'ouvert parade on Blue Hill Avenue around 7:45 a.m.

Two of the people arrested, including one of the possible shooters, were carrying loaded guns modified to let them fire continuously, police say.

According to police, one of the eight people shot, Sebastian Fernandez, 21, was also involved in the shooting, although police say they have yet to find the gun he used.

Police said surveillance video from the scene shows Fernandez and another male, possibly a 17-year-old they arrested later in the day - opening fire on each other.

Police say Fernandez was shot in the leg during the volleys and limped into a nearby tow lot "where he had a tourniquet applied to him by officers and was transported to a local hospital for treatment." He remains at the hospital under police guard.

Police say that the second shooter, wearing a black hoodie with white writing on it "fled on foot into the rear of the Boys and Girls Club towards Franklin Field and made good his escape."

However, police add, around 1:50 p.m., officers spotted somebody matching the description of that person about a mile away on Westview Street in the Franklin Field development.

Officers stopped the individual to conduct a threshold inquiry and found the 17 year old male from Dorchester to be in possession of a Polymer 80 pistol equipped with a "Glock switch" [which turns a gun into an automatic weapon]

He was initially charged with illegal possession of a firearm, but could face further charges as the investigation continues, police say.

Arrested at the scene, by officers already on patrol along the Jouvert route, were Gerald Vick and Dwayne Francis, both 30 and both from Dorchester.

Officers recovered from Vick a 9mm pistol with a large capacity magazine, equipped with a “Glock switch” that enabled the firearm to fire continuously. Francis was found to be in possession of a loaded 9mm Smith and Wesson pistol.

Both were charged will illegal possession of a firearm.

Police say five men, including Fernandez, and one woman were transported to local hospitals with gunshot wounds, none considered life-threatening. Two other people were treated at the scene for graze wounds, police say.

At a press conference Saturday afternoon on Martin Luther King Boulevard, Police Commissioner Michael Cox said the Talbot Avenue shootings apparently stemmed from a beef between two groups who had nothing to do with Carnival. Cox declined to get specific about what led to the shootings, because they remain under investigation.

Mayor Wu, who also spoke at the press conference, called it "heartwrenching" that Carnival would be tagged with this morning's violence. "There's absolutely no excuse for something open to the community and part of Boston's culture and heritage to be talked about this way," she said. "We're going to have a great rest of the day."

She said Boston's Carnival, in its 50th year this year, is one of the largest in the world and a key part of Boston culture.

Like Wu, Shirley Shillingford, a Carnival organizer, said the violence had nothing to do with Carnival. "Kudos to my Boston police, especially to B-3," she said.

The department reported several other incidents Saturday.

Police report gang officers arrested Nakhi Cox-Obryant, 18, of Dorchester at Blue Hill Avenue and Columbia Road after finding her carrying a loaded 9 mm Taurus G2C. She was charged with illegal possession of a firearm, ammunition, a loaded firearm and a large-capacity feeding device.

Around 5 p.m., gang and drug unit officers responding to a report of gunfire at Ellington Street and Old Road, just off Blue Hill Avenue, arrested Maceo Withers-Brewer, 21, of Roxbury on charges of possession of a machine gun, illegal possession of ammunition, possession of a high-capacity magazine and resisting arrest.

Around the same time, officers assigned to Carnival duty arrested a Medford man they say came to town with a gun loaded with 11 bullets, about three blocks away at 522 Blue Hill Ave..

Around 6 p.m., police report arresting a man they say stabbed somebody with a screwdriver at 493 Blue Hill Ave. in Grove Hall.

Police say Michael Josey, 62, of Roxbury, stabbed somebody with a screwdriver in Grove Hall around 6 p.m., then ran away, only to be quickly caught by officers looking for a suspect described as a man with a screwdriver. Police add the victim was taken to a local hospital with injuries not considered life threatening.

Police continue that, also around 5 p.m., officers assigned to Carnival duty along Blue Hill Avenue were flagged down by somebody reporting a guy with a gun.

"Officers were made aware that the suspect was behind a motor vehicle. As officers approached the motor vehicle, they observed two male suspects. Officers immediately were alerted to one suspect as they observed a firearm inside a fanny pack.

"The suspect attempted to reach for the firearm, and a violent struggle ensued. Officers were attempting to handcuff one suspect, and the other suspect attempted to pull the fanny pack from officers. With the assistance of responding officers, the suspect was handcuffed, and the other suspect fled the scene.

"The firearm was later determined to be a Ghost Gun with one round in the chamber and ten rounds in the magazine."

Limondji Simon, 26, of Medford, was charged with illegal possession of a firearm, illegal possession of ammunition and illegal possession of a large-capacity feeding device.

Police report that another person was arrested after a fight around 9:15 a.m. on Blue Hill Avenue between Columbia Road and Seaver Street:

"Officers were flagged down in the area of 590 Blue Hill Avenue for a report of a person with a gun. Officers observed a victim being assaulted by multiple individuals. As officers approached the group, officers observed one of the suspects holding his waistband. Officers attempted to apprehend the suspect, and were pushed by another suspect in the group.

"Officers were able to place one person into handcuffs, while the rest of the group fled the area. Officers recovered a spring-loaded knife from the suspect. Officers continued to canvass the area and located an Airsoft Glock Style pistol."

John Davis, 32, of Roxbury was charged with assault and battery by means of a dangerous weapon, assault and battery on a police officer and illegally carrying a dangerous weapon, police say.

Around 8:50 p.m., police found a man shot in the throat at Blue Hill Avenue and Glenway Street.