A woman who shot dead three people at a Rite Aid distribution center in Maryland was a disgruntled employee working there temporarily, authorities said.
Snochia Moseley, 26, opened fire at the facility near Aberdeen on Thursday -- the latest shooting in the United States and the second workplace rampage in 24 hours.
She killed three people and left three others wounded before turning the gun on herself, authorities said.
A source close to the investigation said Moseley was a disgruntled employee at the facility roughly 30 miles northeast of Baltimore.
She showed up to work at her normal time
Moseley showed up for work at the warehouse, where she was a temporary employee, at her normal time Thursday morning.
She opened fire outside the building and on the warehouse floor, then fatally shot herself in the head with the same 9 mm Glock pistol.
Deputies were dispatched at 9:09 a.m., Harford County Sheriff Jeff Gahler said. Within five minutes, he said, deputies were at the scene, along with the FBI, state police, first responders and other law enforcement authorities.
"You can't have enough police, and you can't have them fast enough, Gahler said.
The sheriff declined to release details about the six victims or the shooter, saying their next of kin are still being notified. Police are still searching for a motive, he added.
Mother texted daughter when gunfire broke out
When the gunfire erupted, Alexie Scharmann got a series of text messages from her mother.
"I love you ... more than you'll ever know," said her mother, who works at the facility near Aberdeen.
"There's a shooter in the building. I'm hiding. I love you," she texted, according to CNN affiliate WBAL. "Be good and take care of dad (and) the pets if something should happen."
Scharmann's mother survived the shooting, and sent her the text message she was hoping for at 10:33 a.m.
"I am outside and safe. I love you," it said.
Shooter was a former security guard
Moseley was once a security guard at the facility where the shooting occurred, a law enforcement official said. She used a gun that she purchased legally, Gahler said, adding that no law enforcement officers fired shots during their response.
Rite Aid spokeswoman Susan Henderson said roughly 1,000 employees work at the distribution center, where products are received and processed for delivery.
"The shooting happened adjacent to the primary building," she said.
Colleen Hendrickson lives and works in the area, and was waiting for the bus when the shooting started.
"I, of course, thought it was far off or, that's like down the road or something, right?" she told CNN affiliate WJZ. "No, it's right outside. It's right on the doorstep."
She saw emergency vehicles, ambulances and helicopters rush to the scene.
"It's really just usually very calm, and this is the most chaotic I've ever seen it," she told the station.
Three shootings in two days
A day earlier, two other shootings made national news.
Police killed the shooters in both incidents Wednesday.
In Harford County, where Thursday's shooting happened, a man killed three people and wounded two others in October at a remodeling business where he worked. The gunman later drove to Wilmington, Delaware, where he shot and wounded a sixth victim.