JACKSONVILLE, Fla. – A man shot and killed his brother Monday evening in a Northwest Jacksonville backyard after the two had some type of confrontation, family members said.

Valerie Currey, who told News4Jax that she's the niece of both men, identified the victim as Marcus Simpson Sr.

Just after 6 p.m., police received a 911 call from a man who said he had just shot someone at his residence on West 15th Street near Witschen Avenue, according to the Jacksonville Sheriff's Office.

When officers arrived, they found Simpson had been shot once in the chest and died, said Sheriff's Office Sgt. Steve Rudlaff.

Police later said they learned that the two had an altercation, during which the victim became armed with a weapon, and the homeowner shot him.

The homeowner was not arrested, but was questioned by investigators, and there are no outstanding persons of interest in the case, Rudlaff said.

News4Jax crime and safety analyst Gil Smith said there's a chance it could have been a case of self-defense.

Currey told News4Jax the two men lived together in the home on West 15th Street.

"It's just crazy to find out that one of them is dead by the hands of another brother. It's just unbelievable. I have family up north who is just freaking out," she said.

According to Currey, last week the two brothers got into another confrontation, in which a gun was drawn.

"They got into a little argument," Currey said. "He pulled out his gun and it jammed. But this time, it didn't jam."

One neighbor, who wished to remain anonymous, said on Tuesday that the two never seemed to have any issues with each other.

"Not really," she said. "I mean, they're brothers. I'm pretty sure they argued, but nothing major."

It has not been confirmed by police, but Currey also said that the victim's son is an officer with JSO and was at the scene Monday night.

“I have my cousin that is one of the officers that is looking into this. It’s his father and uncle. The only thing I can think about is that I got to be there for him because I don’t know how he’s going through this. You’re losing a parent and an uncle at the same time," Currey said.

According to News4Jax records, this was the third homicide in the neighborhood in the last month.