A shooter killed three people Thursday and injured three others before turning the gun on herself at the Rite Aid distribution center in Aberdeen, Maryland, according to the Harford County Sheriff’s Office.

Authorities have identified the shooter as Snochia Moseley, a 26-year-old woman who started working at the center as a temporary employee two weeks before Thursday’s attack.

Update 11:45 a.m. EDT Sept. 21: Deputies identified the three people slain Thursday as Sunday Aguda, a 45-year-old man from Baltimore County; Brindra Giri, a 41-year-old woman from Baltimore County; and Hayleen Reyes, a 41-year-old woman from Baltimore City.

Harford County Sheriff Jeffrey Gahler said Moseley pulled a hooded shirt over her head just after 9 a.m. before she shot Aguda outside of the Rite Aid distribution center. She continued firing shots, which did not hit anyone, and then re-entered the distribution center, where she shot and killed Giri and Reyes.

Deputies also identified the victims injured in Thursday’s shooting.

Gahler said an Aberdeen police officer pulled Moseley from the distribution center after finding her injured on the floor Thursday morning. The officer did not know at the time that Moseley allegedly carried out the attack.

Witnesses told deputies that Gahler shot herself twice after shooting at her co-workers. She died of her injuries later Thursday.

Update 11:35 a.m. EDT Sept. 21: The woman accused of opening fire on her co-workers at the Rite Aid distribution center in Aberdeen was diagnosed with having a mental illness in 2016, Harford County Sheriff Jeffrey Gahler said Friday at a news conference.

Still, Gahler said that Snochia Moseley, a 26-year-old woman who had started work as a temporary employee at the center two weeks before the shooting, was able to legally buy the 9mm Glock 17 she used in Thursday’s attack.

Under Maryland law, people can be barred from purchasing handguns if they’re diagnosed with a mental illness and if they’ve shown a propensity for violence. Authorities said the second part of that criteria had not been met by the time Moseley bought the gun in March.

Authorities did not specify what mental illness Moseley was diagnosed with, though Gahler said investigators found evidence of the diagnosis during a search of her home.

Update 10:55 a.m. EDT Sept. 21: Authorities are expected to provide an update on the investigation into Thursday's shooting at a news conference scheduled for 11 a.m. Friday.

Update 9:10 p.m. EDT Sept. 20: Witnesses at the scene of the shooting Thursday at the Rite Aid distribution center in Aberdeen, Maryland, described a chaotic scene that unfolded after a "town hall meeting" at the facility.

A woman, identified as Snochia Moseley, was reportedly seen arguing with another employee near a time clock at the center before opening fire, according to Krystal Watson, whose husband works in the building, CBS News reported.

"And she went off," Watson told CBS.

"She didn't have a particular target. She was just shooting," she said.

Another witness said the gunman was “shooting like crazy.”

"Everyone was screaming, running this way and that. I didn't know which way to run," employee Walter Zambrano, 64, told CBS.

Another employee with a gunshot wound to the leg made it to a nearby business and told Mike Carre, an employee at a furniture logistics operation, that the shooter "just came in in a bad mood this morning. He said she's usually nice. But today, I guess it wasn't her day. She just came in to pick a fight with someone," Carre said when describing the conversation to CBS.

"She pulled out a gun and she just started shooting at her co-workers,” Carre said.

The Harford County Sheriff Sheriff’s Department said another briefing on the shooting is planned for 11 a.m. Friday morning.

Update 4:53 p.m. EDT Sept. 20: The gunman in the shooting at the Rite Aid distribution center in Maryland has been identified as Snochia Moseley, 26, from Baltimore County, according to the Harford County Sheriff's Office.

Update 3:25 p.m. EDT Sept. 20: The shooter has been identified as a 26-year-old temporary employee. Gahler declined to release her name Thursday, although he said Thursday wasn't her first day at the job.

“(She was) a temporary employee working her normal work day, who reported for her normal work day today,” he said.

Investigators believe she opened fire around 9 a.m. at the Rite Aid distribution center in Aberdeen. Gahler said the shooting appeared to have started outside the facility. It continued indoors, he said.

Deputies said the suspect shot seven people, including herself. Two people died at the scene while a third died at a hospital. Three other people were getting treatment for their injuries, which did not appear to be life-threatening, Gahler said.

Authorities found the suspected shooter on the floor of the Rite Aid distribution center Thursday. She had a self-inflicted gunshot wound to her head, Gahler said.

“She was in critical condition from the outset,” he said.

She used a 9mm Glock handgun that had been registered in her name during Thursday’s attack, according to deputies.

“We do not at this time have a motive for this senseless crime,” Gahler said.

Update 3:05 p.m. EDT Sept. 20: In a statement released to WMAR-TV, Pete Strella, manager of communications for Rite Aid, said the company's distribution center in Aberdeen will remain closed for an unspecified amount of time in the wake of Thursday's shooting.

Update 2:40 p.m. EDT Sept. 20: Dr. Ray Fang, the trauma medical director at Johns Hopkins Bayview Medical Center in Baltimore, said that two of the four people who were taken to the hospital after Thursday morning's shooting were in stable condition. The other two were "very seriously injured," Fang said.

“All four of them came to our trauma center with gunshot wounds,” he said at a news conference Thursday. “Two are stable and doing well and two were very seriously injured and we’re still awaiting confirmation that all their families are aware of their presence here and their injuries.”

He said some injuries were “significant,” and that he believed each patient suffered a gunshot wound to his or her upper body.

Sheriff’s deputies are expected to provide an update on the investigation at a news conference scheduled for 3 p.m.

Update 2:20 p.m. EDT Sept. 20: An unidentified source told CNN that Thursday's shooting at the Rite Aid distribution center in Aberdeen was the work of a disgruntled employee.

According to CNN, the woman shot herself in the head in an apparent suicide attempt. When she was unsuccessful, she shot her self again, the news network reported.

Deputies did not immediately confirm the report.

Harford County Sheriff Jeffrey Gahler said at a news conference Thursday that the suspected shooter was hospitalized in critical condition after the incident. He did not elaborate on her injuries, although he said none of the officers responding to the incident fired any shots.

The shooting marked the third reported workplace shooting in two days, a situation that former U.S. Rep Gabby Giffords said “should spark outrage in every American.” Giffords was shot in the head in 2011 in an attempted assassination.

“No matter where you work, learn, play or live -- you have a right to feel safe, and I’m horrified that that’s no longer the reality in America,” she said. “If gun violence feels like it’s become an everyday occurrence, that’s because it is.”

She urged lawmakers and voters to address the shootings with stronger gun laws.

Update 2:10 p.m. EDT Sept. 20: Deputies are expected to provide additional information about Thursday's shooting at a news conference scheduled for 3 p.m.

Update 1:20 p.m. EDT Sept. 20: Dr. Ray Fang, the trauma medical director at Johns Hopkins Bayview Medical Center in Baltimore, said the hospital was treating four people who suffered gunshot wounds in Thursday's incident.

“We are waiting for confirmation that their families have been notified that they are here and have been notified of their condition before we can give you any specifics about their conditions,” Fang said at a brief news conference Thursday.

Harford County Sheriff Jeffrey Gahler confirmed earlier Thursday that multiple people were killed and several others wounded in the shooting at the Rite Aid distribution center in Aberdeen. He did not specify the number of people killed or elaborate on injuries, however, an unidentified law enforcement official earlier told the AP three people were killed in the incident.

Gahler said the shooter, who has not been identified, was also hospitalized in critical condition after the attack. It was not clear how she was injured or the extent of her wounds. Gahler said none of the officers who responded to Thursday’s incident fired shots.

Authorities continue to investigate.

Update 12:50 p.m. EDT Sept. 20: Sheriff's deputies continued working Thursday afternoon to clear the Rite Aid distribution center where a deadly shooting claimed at least three lives.

Update 12:15 p.m. EDT Sept. 20: Harford County Sheriff Jeffrey Gahler confirmed that multiple people were killed and several others wounded Thursday in a shooting at the Rite Aid distribution center in Aberdeen.

Gahler declined to provide additional details. An unidentified law enforcement official earlier told the AP three people were killed in the incident.

The suspected shooter in the case, who has not been identified, was hospitalized in critical condition after the shooting. It was not clear how the suspect was injured. Gahler said no officers fired shots while responding to the incident.

Authorities responded just after 9 a.m. after they received a report of multiple people shot at the center.

Gahler said investigators believe the suspect used a single handgun in Thursday’s attack. No other suspects are believed to be involved in the incident.

“We are so preliminary into this investigation,” Gahler said. “Keep the victims of today’s tragic events in your thoughts and prayers.”

Update 12 p.m. EDT Sept. 20: Authorities told NBC News that the person who opened fire Thursday at the Rite Aid distribution center in Aberdeen is a woman.

It was not immediately clear how she was connected to the distribution center.

Unidentified officials told WBAL that the suspect was taken to a hospital. It was not clear what injuries she was being treated for.

Authorities are expected to provide additional details at a press conference later Thursday.

Update 11:45 a.m. EDT Sept. 20: A spokeswoman for Rite Aid told CNN that she understands that the distribution center where several people were shot Thursday morning has been secured.

Susan Henderson said about 1,000 people work at the Rite Aid distribution center in Aberdeen.

"The distribution center is where products are received and processed for delivery," she told CNN. "This is part of a large facility that is a distribution center. The shooting happened adjacent to the primary building."

Update 11:35 a.m. EDT Sept. 20: An unidentified law enforcement official told the AP three people were killed in Thursday morning's shooting.

The official was not authorized to discuss details of the case and spoke to the AP on the condition of anonymity.

Update 11:15 a.m. EDT Sept. 20: Officials with Harford County Fire and EMS said Thursday's shooting happened at a Rite Aid distribution center in Aberdeen.

“The scene is still fluid,” officials said in an update issued around 11:10 a.m.

Authorities are expected to provide additional details at a news conference scheduled for 11:45 a.m. Thursday.

Update 11:10 a.m. EDT Sept. 20: A law enforcement official told The Associated Press that multiple people were killed in Thursday's shooting.

Original report: "The situation is still fluid," deputies said Thursday morning. People were asked to avoid the area.

Officials with the FBI’s Baltimore office also responded to the shooting.

Maryland Gov. Larry Hogan described the shooting as “horrific” in a statement Thursday.

“Our prayers are with all those impacted, including our first responders,” Hogan said. “The State stands ready to offer any support.”

Check back for updates to this developing story.