Authorities say a woman accused of killing a young mother and abducting a 3-day-old boy had suffered a recent miscarriage.

Officials in Montgomery County say Verna McClain had told her fiance she had given birth to his child. After she had a miscarriage, McClain allegedly killed Kala Golden and abducted tiny Keegan Golden from outside a pediatrician's office in suburban Houston. Keegan was found unharmed hours later with McClain's sister.

The sheriff's office said Wednesday that McClain tried to represent Keegan as her own child. Her sister allegedly told authorities that McClain had plans to "do the adoption" after taking Keegan.

McClain now faces a capital murder charge and is being held without bail. Her fiancee, who was not identified, is being interviewed by authorities.

An Amber Alert was issued Tuesday afternoon for Keegan Schuchardt after the baby was kidnapped at a pediatrician’s office around 2:40 p.m., MyFoxHouston.com reported.

Golden was placing her newborn son inside her pickup truck when she got into an altercation with someone in a car parked next to her, according to the Montgomery County Sheriff’s Office. Golden was shot several times, the report said.

When Golden tried to get Keegan out of the suspect's car, a four-door Lexus, she was knocked to the ground as the suspect allegedly drove away, the report said. The dying woman leaned into the vehicle and tried to take Keegan back, screaming "My baby!" but her attacker sped away.

Golden was later taken to Memorial Hermann Hospital where she was pronounced dead.

Authorities said at an afternoon press conference that McClain recently had a miscarriage and wanted to produce a child for fiance. She has been placed in a single cell and is not on suicide watch.

Golden's mother, Linda Golden, told the Associated Press that she had been baby-sitting 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.

Joshua Jesson said he was at the clinic with his girlfriend when he heard gunshots. He said he saw a Lexus next to the pickup truck, then later looked back and saw the car was gone and a woman lying in the spot where the Lexus had been parked.

"I thought she just passed out. Then somebody ran in here and said, `Somebody got shot,"' he said.

Police quickly surrounded the clinic and much of the parking lot with crime-scene tape, and yellow markers were placed next to a purse and pair of brown sandals near a red pickup truck. Spent ammunition also was nearby.

Linda Golden described her daughter as sweet-natured and kind.

"We went everywhere together and did everything together," she said.

She 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."

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The Associated Press contributed to this report.