As Cpl. Rodolfo Rivera Valencia told it, his first thought the morning after the Marine Corps’ 243rd Birthday Ball was that he had a heck of a hangover.

The second thought, he said, was to ask why his 20-year-old wife, Lance Cpl. Natasha Soto Rivera, was no longer breathing beside him in bed.

In a call to emergency services made at 9:40 a.m. from his hotel room at the Crystal Gateway Marriott in Arlington, Virginia, the Marine told the dispatcher he found his wife unconscious and he believed he had killed her, according to a search warrant affidavit.

“Upon arrival, officers located a female victim deceased inside a hotel room,” Arlington County Police said in a press release. “The suspect was on scene when police arrived and taken into custody without incident.”

At the scene, Arlington Detective Jasmine Sean noticed that Natasha Rivera’s face indicated she suffered a “brutal” beating, according to court records. The bruising to her arms and neck were consistent with strangulation, Sean noted, though the coroner’s office has not yet determined an official cause of death.

The pregnant mother of one, who was also a Marine, was declared dead by arriving medics at the hotel, the same place where the Marine gala had taken place the previous evening.

According to authorities, Rivera Valencia, 23, later admitted to police he did not render medical aid or immediately call 911 when he realized his wife “of seven or eight months” was unresponsive.

The Marine also told investigators that he and his wife were the only people in the hotel room after the ball, though he did not fully remember events of the night, court records stated.

Within hours, he was arrested and charged with murder, and he is being held without bond at the Arlington County Detention Center until his scheduled hearing in December for what police called a "domestic-related homicide."

“At the moment we are still grieving and would not like to talk,” Marilyn Soto, Natasha’s sister, told The Daily Beast.

“No words can't explain how I feel right now,” Evelyn Crespo, Natasha’s mother, wrote on Facebook, the day after her daughter was found dead. “I lost my daughter Natasha Soto, by someone she loved and trusted. I still can't believe it and accept that my little Marine is gone. Please I am asking for your prayers for our family especially my little grandson in this moment of pain.”

Another sister, Marilyn, wrote on Facebook, “It’s crazy how you can lose somebody in a matter of minutes. My sister was an amazing mother, amazing sister and wonderful friend. She is the best person anybody could have ever meet.

“ I don’t understand how a person could do this to her when she has never done anybody wrong. ” — Marilyn Soto

“I don’t understand how a person could do this to her when she has never done anybody wrong.”

In a series of interviews with police, Rivera Valencia said he didn’t understand it either.

He allegedly admitted that the night of the ball, he drank to the point of “blacking out” somewhere between the Marine Corps dinner and when the dancing started, and could not remember anything that happened. Rivera Valencia also mentioned having an anger problem, according to police.

The Arlington Police Department and Naval Criminal Investigative Service are now investigating with “full cooperation” from Quantico, where the newlyweds were based with their infant child, the agency confirmed.

“ We are shocked and saddened by this tragic loss,” Maj, Ken Kunze, communication strategy and operations officer for the Marines’ Quantico office, told The Daily Beast. “Our deepest sympathies are extended to the Marines and families involved.”

Rivera Valencia, originally from Cook County, Illinois, had joined the Marine Corps on March 14, 2016. His wife, a Brooklyn, New York native, joined the Marine Corps on April 17, 2017. The two worked together in the Legal Services Support Section at the base in Quantico—their first duty station.

The two legal-services specialists had not yet been deployed, but both were already awarded the National Defense Service Medal and Global War on Terrorism Service Medal, the Marine Corps confirmed to The Daily Beast.

After meeting during training in Quantico, the two were married on April 29 and welcomed their first child, Mateo Tobias, five months later, friends of the couple told The Daily Beast.

“How did we get so lucky Rodolfo Rivera,” Natasha wrote on Facebook, along with two photos of their newborn baby boy.

Friends of Natasha said she was living out her dream at the time of her death, both as a lance corporal in the Marine Corps and as a mother.

“She was full of life, she had more to give and it was taken away from her,” Leyda Cruz, a family friend, told a local news station at the time. “She didn’t get to raise her baby. It’s not fair what he did.”

Cruz said that Soto Rivera was a “tough girl” who probably fought her husband during the alleged attack, adding she just wanted “the world to know she is a hero.”

Now, almost two weeks later, authorities have searched the couple’s home and have seized several items in this fast-moving investigation, including an iPhone and a laptop, according to court records.

Evelyn Crespo, Natasha’s mother, is hopeful that the investigation will yield answers, and is demanding people let the police do their job before jumping to conclusions about what happened that night, especially since the findings are so preliminary.

“I am getting upset that many people are assuming what happen to my daughter, the investigation is still ongoing and I still don't have any autopsy report. The investigators are still investigating. The Marine Corps is still doing their thing and just release her rank and what she did,” Crespo wrote on Facebook a few days after Rivera Valencia was arrested. “Please stop talking and let the investigation go on and when is done everyone will know.”