ABERDEEN, Md. -- Workers say they endured horrifying moments of wild gunfire and terror as a woman working a temporary job at a drugstore warehouse in Maryland fired on colleagues with a handgun, killing three people before fatally shooting herself, according to authorities. CBS News' Mola Lenghi reports that witnesses say the shooting followed an argument Thursday morning between the suspect and another employee.

The shooting sent survivors screaming and running in all directions from the Rite Aid distribution center in northeastern Maryland. Others nearby helped the wounded, and one person tied blood-soaked jeans around an injured man's leg trying to stanch the bleeding.

Krystal Watson said her husband Eric works at the facility and told her told her the suspect had been arguing with somebody else near a time clock after a "town hall meeting."

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"And she went off," she said.

"She didn't have a particular target. She was just shooting," Watson said as she left a fire station where relatives sought to be reunited with loved ones.

Worker Walter Zambrano, 64, said he was fortunate that he was in a bathroom when shooting broke out during a 9 a.m. morning break when workers were gathering in a cafeteria. He hid in the bathroom until the shooting stopped, fearing for his life.

The person was "shooting like crazy, bam! bam! bam!" Zambrano said, speaking in Spanish. "Everyone was screaming, running this way and that. I didn't know which way to run."

The Harford County sheriff's office has said the woman was identified as a temporary employee, Snochia Moseley of Baltimore County. It appears only one weapon was used - a 9 mm Glock handgun that was registered in Moseley's name - and no shots were fired by responding law enforcement officers, Sheriff Jeffrey Gahler said.

"She had reported for her workday as usual, and around 9 a.m. the shooting began, striking victims both outside the business and inside the facility," Gahler said at a news conference.

He called it a "senseless crime," adding investigators hadn't identified a motive.

According to a recent FBI study, men carried out 94 percent of mass shootings between 2000 and 2013.

Three people were fatally shot and three more were wounded but expected to survive, the sheriff said. The victims were not immediately identified. Moseley died at a hospital from a self-inflicted gunshot wound, according to the sheriff.

Gahler said the call about shots fired came in at about 9:06 a.m. Thursday and deputies and other officers were on the scene in just over five minutes. The shooting began outside the business and continued inside, he said.

CBS News correspondent Chip Reid reported one woman in the building sent a text to her children, writing, "I love you. Be good an take care of daddy an the pets if something should happen."

Susan Henderson, spokeswoman for the drugstore chain Rite Aid, described the building where the shooting took place as a support facility near a larger building. The company said in a statement that the facility had been closed temporarily and grief counselors were being made available to workers.

The company didn't respond to an inquiry about Moseley's employment history.

Mike Carre, an employee of a furniture logistics operation next to the distribution center, said he helped tend to a wounded man who came hobbling in, bleeding from his leg. He called 911 before helping colleagues wrap the man's blood-soaked jeans above his injury to cut off the blood flow.

Carre said the man told him 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."

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

The attack came nearly three months after a man with a shotgun attacked a newspaper office in Annapolis, Maryland, killing five staff members. Authorities accused Jarrod W. Ramos of attacking The Capital Gazette because of a longstanding grudge against the paper. It came less than a year after a fatal workplace shooting less than 10 miles from the warehouse, in which five were shot, three fatally.

Harford County Executive Barry Glassman said that, unfortunately, shooting like this are "becoming a too-often occurrence" in the nation.

On Thursday, 33-year-old Dominique Norton of Aberdeen endured an excruciating wait of nearly two hours to be reunited with her mother, 62-year-old warehouse worker Irene Norton. The younger woman said she didn't know that her mother was unharmed until she got off a bus at the fire station and they tearfully embraced.

"I busted out crying. I was relieved and shaken," she said. "I am praying for all of the victims."