SPOTSYLVANIA, Va. -- A 15-year-old boy has been charged with 2nd Degree Murder and Use of a Firearm During the Commission of a Felony for shooting and killing a man who investigators said was attacking his mom inside a Spotsylvania home Tuesday afternoon, according to the Spotsylvania County Sheriff’s Office.

The man, identified as 37-year-old John Conroy Jr., was the mom's boyfriend, investigators said.

Sheriff's deputies found Conroy inside the Towles Mill Road home when they responded to the house at about 3:45 p.m. Tuesday.

Capt. Jeff Pearce said earlier that day Conroy and his 36-year-old girlfriend got into an argument that lasted for hours. Then, he physically attacked her while the woman's son watched.

"At that point, the 15-year-old son went to a place in the home where he knew there was a firearm," Spotsylvania Sheriff’s spokesman Capt. Jeff Pearce said ."[He] took a semiautomatic firearm from a nearby location in the room and fired several shots at Conroy, striking him multiple times."

The teenager's mother was treated for non-life threatening injuries.

Detectives, in consultation with the Spotsylvania Commonwealth Attorney’s Office, filed petitions for the arrest of the teenager who fired the shots, Pearce said.

Pearce said under Virginia law all homicides are considered second-degree murder.

"When the investigation is concluded the Commonwealth's Attorney can do everything from raising it to a more serious charge, lessening it to a less severe count or dismissing it all together," Pearce added.

"The investigation is still in the early stages and is ongoing. A myriad of evidentiary items, statements, interviews and further investigative assignments are underway," Spotsylvania Sheriff Roger L. Harris said.

Pearce wouldn't go into details about the relationship between the teen and Conroy or if the couple had previous problems, but he noted their tragic end.

"Each and every time you see something like this it still gets to your heartstrings because this is a family that has been destroyed," Pearce explained.

The 15-year-old suspect is being held at the Rappahanock Regional Jail. There has been no word on when of if he could be released on bond.

Neighbor stunned

"I didn't know what was going on," said Johnny Jackson, a neighbor who described the chaotic scene in his Spotsylvania neighborhood.

"Everything was quiet since yesterday evening," Jackson said. "We saw all that and heard the sirens and went outside and looked."

Jackson said a convoy of police cruisers including a K-9 unit flooded the home on Towles Mill Road.

"It's terrible... I tell you that," Jackson said.

This is a developing story. Anyone with more information about this incident can submit a news tip here.