UPDATE December 2, 2018:

The Associated Press reports that on November 30, 2018, a judge sentenced 37-year-old U.S. Army Sgt. Maliek Kearney to life without the possibility of parole. He was convicted of the murder of his estranged wife in August 2018. Kearney was also ordered to pay nearly $500,000 in restitution to his wife’s family.

Kearney's girlfriend, Dolores Delgado, testified that she provided the gun. She allowed him to drive her car from South Carolina to Maryland.

MORE: Army sergeant gets life without parole for slaying soldier wife - Army Times

UPDATE August 8, 2017:

Dolores Delgado, age 32, of San Antonio, Texas, pleaded guilty in federal court for interstate travel to commit domestic violence resulting in death, in connection with the death of Karlyn Ramirez.

According to the statement of facts supporting the plea agreement, Karlyn Ramirez was an active duty soldier of the United States Army assigned to Fort Meade, Maryland. She was found shot to death in her off-post residence on the morning of August 25, 2015. Her four-month old daughter had been placed in her arms. Forensic evidence estimates the likely time of death was during the late evening hours of August 24, 2015.

UPDATE Oct. 6, 2016: Two people were arrested in San Antonio in connection with the murder of Karlyn Ramirez. Maliek Kearney and his girlfriend Dolores Delgado were taken into custody on federal warrants out of Maryland, where a federal grand jury had indicted them Tuesday, MySanAntonio.com reports.

Kearney and Delgado are charged with interstate travel to commit domestic violence resulting in the Aug. 24, 2015 death of Karlyn Ramirez, according to MySanAntonio.com.

A military mom with top-secret security clearance is gunned down in her Maryland home on August 25, 2015.

Karlyn Ramirez was 24. When police found her, she wasn't alone. But the only living witness can't say who killed her.

Karlyn grew up in the small border town of Del Rio, Texas, a shy girl who would become a warrior.

She left college to join the United States Army. After enlisting at 21, she was eventually sent to South Korea as a Private First Class.

Karlyn not only adjusted, she thrived, and ended up falling in love with Staff Sergeant Maliek Kearney. Then came the most welcome of surprises: She found out she was pregnant. Karlyn, a cervical cancer survivor, was told she would probably never have kids. She proved them wrong.

Two weeks before coming home from Korea, the U.S. National Security Agency offered her a position in Maryland with top-secret security clearance.

Karlyn was happy at her new job, but the day she had her daughter Vale was the happiest of her life.

Eventually Karlyn and Maliek married, but he was stationed in South Carolina, and the couple was often apart.

Feeling lonely, Karlyn invited her sister Roxanna to stay in her townhouse, located in a safe 600-unit community near Fort Meade, Md., where a lot of military families live.

A few months later Roxanna moved back to Texas, and a military friend of Karlyn's moved in.

"Her friend Marissa was staying with her and she had a little girl," said Susan, Karlyn's mother. "They were best buds."

Life was good. Then one August night, Karlyn placed alarming out-of-character calls to both her sister and mother.

"She said 'I don't know what is wrong. I don't feel right. I don't feel safe. Do you think my baby knows I love her?'" said Roxanne. "I am like, 'Why are you talking like this? What happened?' 'I don't know. I can't tell you. I don't know.'"

"She told me she was having a panic attack, and I said 'Karlyn, what's wrong,' and she said 'I can't discuss it. It's nothing I can discuss with you,'" said Susan. "I automatically thought: work."

Karlyn calmed down and Susan ended the call like she always did: "With 'I love you, always,'" said Susan. "'Always,' and that was it."

"I did not feel comfortable that night when we hung up and I couldn't sleep," said Roxanne. "I sent her a text. My phone said she read it. I really think she did. I don't know exactly. But that was our last conversation."

"I called her, she didn't answer. I called her again," said Susan. "She didn't answer. I texted her, she didn't answer."

On August 25, 2015, around 8 a.m., maintenance workers saw two dogs running loose.

"When they went to corral them the dog ran back into an open door in the town home, so they went back around to the front and knocked on the door and got no answer," said Anne Arundel County Police Sergeant John Poole.

They called the police, and when cops arrived they found Karlyn Ramirez had been shot multiple times and was dead. Her 5-month-old baby was there, unharmed.

But who wanted this loving mother and soldier dead?

With not much to go on, cops did exactly what they always do, first looking at the two people they felt were closest to Karlyn: her roommate and her husband.

Maliek and Karlyn had been married only five weeks at the time of the murder.

"They were a newly married couple, there was no separation agreement," said Sgt. Poole. "However there was a bit of tension because he was stationed in South Carolina."

Although police considered Karlyn's husband an official person of interest, they quickly determined he was in South Carolina at the time, and his alibi checked out.

Police were soon able to confirm that Karlyn's roommate was in Washington state with her daughter visiting family at the time of Karlyn's murder.

"As far as the roommate and the husband, we aren't going to say they've been cleared, but they have definitely been cooperative and everything has checked out so far," said Poole.

The question if someone related to Karlyn's top-secret high-security clearance job could have had anything to do with it remained unanswered.

Cops were keeping details close to the vest.

"They keep telling me this in an active investigation and there's so many things we can discuss with you, but they felt like she may have known who did it. She let them in, nothing had been stolen from what they could tell," said Susan. "Someone told me that it looked like a professional hit. Someone had to have known Karlyn was there by herself."

Susan believed Karlyn, who was a mixed-martial-arts fighter, would have defended herself if she could -- with one exception:

"If she didn't put up a fight, it was to save her child. That's probably the only thing that would have stopped her," said Susan. "He would have fought to her last breath, and I don't know that she didn't."

Police say there is no obvious motive.

"Karlyn was a very well-loved young lady, a new mother, a new wife and had a bright career as a soldier," said Sgt. Poole. "You can't explain or imagine that someone so loving and caring, something this tragic and senseless could happen to them."

And in the midst of this still very raw unsolved tragedy, taking care of Karlyn's daughter Vale is what the family is focused on.

Now police need the public's help.

The family says Karlyn's husband Maliek has been very involved in his daughter's life since that tragic day, and he's transferred to a base closer to them so he can see her more often.

Police say this is an active case. Because Karlyn was stationed at many bases, they have interviewed hundreds of people around the country, and they are about to head out again to conduct some more follow-up interviews.