Alfonso Heredia said his family felt some relief after his sister's killer and niece's kidnapper was sentenced to life in prison.

"It took a weight off our shoulders," Heredia said. "It didn't bring peace to our hearts, but it brought a weight off our shoulders."

Adriana Lisa Castillo Perez, 31, of Canadian, pleaded guilty Wednesday to capital murder in the Dec. 23 killing of Leslie Escobar Perez, 23, of Shamrock.

Adriana Perez lured Leslie Perez into an encounter at the family's home in Shamrock with the promise of free baby clothing, a crib and other items, and then stabbed the woman multiple times before fleeing with Abcde Perez, her 2-week-old daughter, 31st District Attorney Franklin McDonough said.

The two women were not related, authorities said.

As part of a plea bargain with 31st District Attorney Franklin McDonough, Adriana Perez will serve life in prison without the possibility of parole, court documents show.

McDonough said Adriana Perez had formulated a "very elaborate plan" before meeting Leslie Perez on Facebook. She had determined she was going to kidnap a child, and had visited a Facebook group dedicated to buying and selling items in search of a target.

On Facebook, she saw a status Leslie Perez had posted expressing her excitement about having a new baby. From there, Adriana Perez contacted Leslie Perez about giving away items for the baby.

The two arranged to meet at Leslie Perez's home on December 23, where authorities said Adriana Perez stabbed her multiple times and fled with Abcde.

Authorities found Leslie Perez outside the home where she had crawled after being stabbed.

"She … fought for her life," McDonough said. "She fought for that baby."

A neighbor reported a strange vehicle had been at the family's home earlier in the day. The neighbor described the vehicle to police and authorities broadcast an alert to nearby law enforcement agencies.

Adriana Perez was stopped as she drove to Pampa by a Gray County Sheriff's deputy later that night. She had the infant and the murder weapon in her possession, McDonough said. Abcde had not been injured.

Texas Rangers led the investigation, with Shamrock police, Texas Department of Public Safety troopers and sheriff's officials in Gray and Wheeler counties assisting.

Maxwell Peck, a defense attorney with the Regional Public Defender for Capital Cases office in Lubbock, represented Adriana Perez.

"We got to a point legally where we felt like if we could resolve the case for life without the possibility of parole, that's what needed to happen," Peck said. "And, thankfully, the victim's family felt like that was enough justice for them and the district attorney agreed and our client agreed to accept responsibility."

Leslie Perez's family members said they were satisfied with Adriana Perez's sentence.

"I think I feel pretty good," Anna Garcia, Leslie Perez's mother, said. "I'm glad she got what she deserved. It's not going to take my pain away, but, I know she's going to be where she won't hurt nobody else."

Garcia is now raising Abcde. She said she hopes the healing process for her family can begin.

"We've been through a lot," Garcia said. "Our family kind of separated over this. We really don't talk. We suffer a lot. We don't sleep, eat. We argue a lot. … Maybe now that everything's settling down we can get back together again, to the family we used to be. It won't ever be the same, because now there's somebody missing there, but maybe we can get through it now."