Authorities are investigating whether a gunman accused of killing eight people at a North Carolina nursing home may have targeted the facility because his estranged wife worked there, police said.

Carthage Police Chief Chris McKenzie said the woman, whom he did not name, worked at the nursing home. He said he believed that the couple were recently separated but that he did not have any other details. He was not sure if the woman was at the nursing home at the time of the shootings.

Authorities said Robert Stewart, 45, went on a terrifying rampage in the Pinelake Health and Rehab center in Carthage on Sunday morning, killing seven residents and a nurse and wounding three others.

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"We're certainly looking into the fact that it may be domestic-related," McKenzie told The Associated Press.

The News & Observer of Raleigh reported Monday that Stewart's estranged wife is Wanda Luck, who works as a certified nurse assistant at the nursing home. Public records indicate she shared an address with Stewart in Carthage. Mark Barnett, a neighbor of Luck's parents, told the newspaper that Luck was working at the home on Sunday.

Police could not immediately confirm Luck's identity.

An ex-wife of Stewart's, Sue Griffin, told reporters Sunday she had not had contact with him since they divorced in 2001 but that he had "violent tendencies." Griffin added she didn't know how her ex-husband was connected to the nursing home or why he would shoot people there.

The injured included a police officer hailed as a hero for shooting the gunman before more people could be killed.

Officials said 25-year-old Carthage Police Officer Justin Garner wounded Stewart with a single gunshot to the uppper torso while trading gunfire in a hallway. Garner himself was shot three times in the leg.

"I can’t classify it as anything other than heroic," McKenzie said. "If that’s not heroism, I don’t know what is. A lot more lives would have been lost if he hadn’t done what he did."

Griffin, Stewart's ex-wife, said Stewart had been recently reaching out to family members, telling them he had cancer and was preparing for a long trip and to "go away."

Griffin said she was married to Stewart for 15 years, and while they hadn't spoken since divorcing in 2001, he had been trying to reach her during the past week through her son, mother, sister and grandmother.

"He did have some violent tendencies from time to time," Griffin said. "I wouldn't put it past him. I hate to say it, but it is true."

Court records said Stewart was transferred from the custody of Moore County to the state Department of Correction, because he has a gunshot wound. He is not scheduled to appear in court until next week on eight counts of first-degree murder and a charge of felony assault of a law enforcement officer.

Stewart was not a patient or an employee at the nursing home and wasn't believed to be related to any of the victims, authorities said.

Families waited anxiously near the home Sunday for news of their loved ones.

"My heart stopped, because I didn't know what had happened. I thought maybe something had happened to my mom," said Easter Butler, who learned her mother was unhurt.

Krueger said the victims were Pinelake residents Tessie Garner, 88; Lillian Dunn, 89; Jessie Musser, 88; Bessie Hendrick, 78; John Goldston, 78; Margaret Johnson, 89; Louise Decker, 98; and nurse Jerry Avent, whose age wasn't immediately available.

Musser had lived at Pinelake for only six weeks, said his son-in-law, Jim Foster, 47, of Aberdeen. He said the man had Alzheimer's and Parkinson's diseases and was blind, deaf and confined to a wheelchair. Foster said the family was now trying to figure out how to tell Musser's wife, who has dementia and lives at the same facility, that her husband is dead.

"She was upset that they didn't bring him to see her yesterday," Foster said. "I don't know how we're going to break it to her. You got a clue?"

Beverly McNeill said her mother, Pinelake resident Ellery Chisholm, called moments after the gunman stormed into her room and pointed his "deer gun" at her roommate. "They're up here shooting, they're up here shooting," Chisholm frantically told her 14-year-old granddaughter, Tavia, over the phone, McNeil said.

Chisholm told her daughter that she hid her face in her shirt so she couldn't see the man or what she expected him to do, McNeill said. He didn't shoot, but left the room and began shooting down the hallway.

The facility was closed after the attack as authorities worked to gather evidence inside and out. Krueger declined to say if authorities had moved the surviving residents from the 110-bed facility, including patients with Alzheimer's disease, saying only, "They're safe, which is the primary thing."

Among the items investigators found was a camouflaged-colored rifle or shotgun, which was leaning against the side of a Jeep Cherokee in the parking lot.

Sunday's rampage happened just weeks after a man killed 10 people, including his mother and several other relatives, in the worst mass shooting in Alabama's history on March 10. On March 11, a teen killed 12 people at his former high school in Germany.

The Associated Press contributed to this report.