A woman shot and killed in an eastern Iowa shopping mall was a 20-year-old employee of a children's museum inside the mall and knew the man who shot her, authorities said on Saturday during a news conference.

Coralville police said Andrea Farrington, of Cedar Rapids, was shot multiple times in her torso, and that a handgun and three 9mm casings were found at the scene. Witnesses have said she was shot in the back, and several people came to her aid to try to staunch her bleeding and perform CPR. Farrington died at an Iowa City hospital.

Officials have charged 22-year-old Alexander Matthew Kozak, of North Liberty, with first-degree murder in the shooting that occurred Friday evening inside Coral Ridge Mall near its food court. No one else was injured.

Kozak was arrested a short time after the shooting. He is being held on $10 million bond.

Johnson County Attorney Janet Lyness said police believe Farrington was targeted, saying Kozak told an investigator that he had left the mall, retrieved a gun from his home and returned to shoot Farrington. Authorities declined to discuss a motive, saying only that the two knew each other from working at the mall.

Officials confirmed that Kozak was a security guard at the mall. Authorities do not believe there were any other suspects.

Soon after the shooting near the mall's food court, troopers spotted Kozak's car on Interstate 80 near Davenport about 50 miles east of the mall and arrested him without incident.

Kozak's case did not appear Saturday in online court records for Iowa, and it was unclear who would be appointed to serve as Kozak's attorney.

Witnesses to the shooting told the Iowa City Press-Citizen that several shots rang out near the mall's carousel entrance at about 7:30 p.m.

Ryan Ross, who said he works at a mall kiosk, told the Press-Citizen he recognized the shooter as a security officer who had been fired earlier in the day.

Jeff Carew, of Tiffin, said the woman was shot in the back with a handgun.

"I heard three shots and watched the girl fall," Carew told the Press-Citizen.

In an email to The Associated Press on Saturday, the mall's general manager, Monica Nadeau, said mall officials are cooperating with police, but did not respond to questions about Kozak's employment with the mall or whether he had been fired before the shooting.

The mall is along a busy stretch of Interstate 80 in Coralville, a normally quiet, suburban community of about 19,000 people in eastern Iowa. Coral Ridge is the second-largest mall in Iowa, and it has long been a regional shopping destination.