BALTIMORE (WJZ) — Investigators now believe an officer fired the shot that wounded a 5-year-old boy during a deadly standoff between his mother and police at a Randallstown apartment complex on Monday, authorities said.

There is a continuing investigation into the shooting, which followed a 7-hour standoff at an apartment complex on Sulky Court, that killed 23-year-old Korryn Gaines and injured her son.

“There were times that we thought this would come to a peaceful resolution,” Baltimore County Police Chief James Johnson said at a Tuesday news conference. “There were other times she was highly agitated. The entire time throughout the afternoon, she would repeatedly point the gun at her personnel.”

At a vigil held for Gaines on Friday night, loved ones said police should have relied more on family members to save her life.

“They did not use their most precious tool to save her life,” said cousin Creo Brady. “It is your job to save lives, not take them, and they did not use every tool available to them to save a life.”

RELATED: ‘Patience’ Needed During Korryn Gaines Shooting Investigation, Police Say

It all started when police went by Gaines’ apartment about 9:20 a.m. that day with a warrant for her arrest and another for her boyfriend, according to police.

After multiple knocks at the door went unanswered and overhearing voices inside, officers got a key from the landlord and opened the door, police said.

That’s when officers could see Gaines seated on the floor, armed with a 12-gauge shotgun, and a child nearby, police chief James Johnson told reporters at a news conference the following day.

RELATED: ‘Unprecedented Number’ of Threats Received After Gaines’ Shooting

Officers retreated to the hallway and called for backup, according to police. Tactical teams surrounded the home and negotiations with Gaines got underway about 9:40 a.m.

At some point, Gaines’ boyfriend, 39-year-old Kareem Courtney, ran out of the home with a 1-year-old child and was taken into custody without incident on a warrant for second-degree assault, police said.

Gaines remained inside, broadcasting her standoff with police on social media. Police, who deactivated her accounts by contacting Facebook, have said her social media followers were discouraging Gaines from surrendering peacefully.

RELATED: Armed Woman Killed in Shootout With Police, 5-Year-Old Injured

As the hours passed, negotiators spoke with Gaines over the phone and face to face, according to police.

Those negotiations broke down about 4 p.m. when officers tried to coax Gaines into surrendering. She refused, according to police, and instead pointed the shotgun at officers, allegedly even threatening them at one point with the warning, “If you don’t leave, I’m going to kill you.”

That’s when, Johnson said, a tactical officer fired a round at Gaines, who returned fire. Officers then fired back, fatally shooting Gaines.

“Our officer returned three rounds of fire, striking her and killing her,” said Johnson.

Gaines’ son, Kodi, was wounded in the arm and left cheek during the exchange of gunfire, according to police. He was hospitalized, where he remains in good condition.

Police have said none of the officers dealing directly with Gaines was equipped with a body camera during the incident. The county launched its program — which will eventually have 1,400 officers wearing them — about a month ago.

Following the shooting, police released charging documents from the traffic stop that led officers to serve the warrant on Gaines. On March 10, she was pulled over for having cardboard on her car where her license plates were supposed to go.

“Any government official who compromises this pursuit to happiness and right to travel will be held criminally responsible and fined as this is a natural right and freedom,” the rear piece of cardboard said, while the one in front read, “Free traveler.”

Police alleged Gaines, who had two children in her car, was uncooperative during the stop and at one point told an officer he had no right to pull her over and would have to “murder her” to get her out of the vehicle.

When Gaines refused to exit, she was placed under arrest during a brief struggle in which she allegedly told her son to “fight and bite the officer” who was holding him.

For that incident, Gaines was charged with disorderly conduct and resisting arrest. She later missed a court hearing for those charges and a judge issued a warrant for her arrest.

Police have not yet identified the officer who fired the rounds that killed Gaines.