SPRING, Texas - A nurse admitted to fatally shooting a young mother in a town near Houston and abducting the dying woman's newborn son whom she apparently intended to adopt, authorities said Wednesday.

Verna McClain is charged with capital murder in the killing of 28-year-old Kala Marie Golden. Witnesses saw a woman repeatedly shoot Golden on Tuesday afternoon in the parking lot of a pediatric clinic in Spring. She then drove away with Golden's 3-day-old son Keegan who was found Tuesday evening, unharmed, at a home with McClain's sister, authorities said.

According to an arrest record, McClain, 30, admitted to shooting Golden and taking Keegan to Harris County, where the baby was subsequently found. Houston is in Harris County and McClain listed an address in the city as her home, according to jail records.

McClain gave authorities information that only the shooter would know, according to the arrest record.

She is being held without bail.

The Sheriff's office said in a statement that officers found Keegan with Corina Jackson, McClain's sister. Jackson told investigators that McClain told her she would need to "do the adoption," according to the county record.

District Attorney Brett Ligon said McClain's statement to investigators indicates she shot the mother as part of a wider plan to kidnap any child and that Golden was simply in the wrong place at the wrong time.

"We believe we have sufficient evidence to prove that she kidnapped the child and committed the murder," Ligon said at a press conference Wednesday.

Ligon said McClain approached law enforcement at an apartment complex where detectives found a vehicle matching the description of witnesses and started to provide information about the case. But McClain did not say where the child was, Ligon said.

Instead, authorities received an anonymous tip that directed them to Keegan's location, he said. McClain was then arrested at the apartment complex and later confessed to authorities.

McClain's sister lives at the apartment complex that detectives searched before they found the child, Ligon said. It remains unclear who lived at the home where Keegan was found, Ligon said.

Keegan has been released to family members, according to his father, Keith Schuchardt.

Witnesses say an argument broke out on Tuesday afternoon between Golden and another woman as Golden left Northwoods Pediatric Center in Spring, about 20 miles (32 kilometres) north of Houston.

The woman repeatedly shot Golden then snatched Keegan from her and began to drive away in a blue or light green Lexus, according to witness accounts. The dying woman leaned into the vehicle and tried to take Keegan back, screaming "My baby!" but her attacker sped away.

Keith Schuchardt said he told the Houston Chronicle that he and Golden had been married for three years. Schuchardt said he learned of the shooting because as Golden lay dying she asked another woman to call him and tell him what had happened.

"I loved her, and she loved me," Schuchardt told Houston television station KHOU. "Everything was going fine until today."

Schuchardt told The Associated Press Wednesday that family members had custody of Keegan and two siblings. Schuchardt said officials were concerned about his criminal record, which includes felony convictions for possession of a controlled substance and burglary of a coin-operated machine.

McClain, a vocational nurse, is not employed by the Northwoods Pediatrics Center, according to a receptionist at the clinic, Jackie Longoria. She is married with two children but has been separated from her husband for two years, said her husband, Theo McClain. The couple also raised another child that was his from a previous relationship, he said.

"I don't understand that, her taking a child," Theo McClain told the AP. "That doesn't make sense. We have three kids. And then to shoot somebody? I've never known her to hurt anybody."

McClain has obtained vocational nursing licenses in both California and Texas. She has not faced disciplinary action in either state, according to each state's respective licensing board.

Vocational nurses provide basic nursing services under the direction of registered nurses and doctors.

Golden's mother, Linda Golden, told the AP that she had been babysitting another of Kala's sons when someone at the scene called her using her daughter's cellphone. She rushed to the clinic but was unable to see her daughter because paramedics were trying to save her.

"I wanted to kiss her before they put her in the ambulance," Linda Golden said.

Linda Golden said she had no idea what could have sparked the slaying and abduction.

"That's the hardest she's ever fought," Linda Golden said. "She died trying to save her baby."