Nikki Alcaraz and boyfriend Steven Tyler Stratton set off on a cross-country road trip in her Jeep Wrangler, made it out West and reportedly got into a public fight, although police split the couple up and made no arrests.

Then, she went missing – although police say they spotted her over the weekend at a California Walmart, according to local reports.

According to an incident report obtained by Fox News Digital, a witness told a deputy he saw Stratton punch Alcaraz in the face on the side of Interstate 40 on May 4. Authorities were already on the way to the scene after dispatch received a call from a screaming woman who abruptly stopped responding.

They arrived to find her covered in bruises – but Stratton was also bleeding from the face so badly that there was blood running down the side of the car. Deputies determined them to be "mutual combatants."

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Nikki Alcaraz and Steven Tyler Stratton wearing black

Nikki Alcaraz, right, vanished from a cross-country road trip with her boyfriend Steven Tyler Stratton, according to deputies in Cheatham County, Tennessee. The couple was reportedly involved in a domestic dispute in New Mexico along the way, but no charges were filed. (Cheatham County Sheriff's Office)

"Mr. Hamilton (the witness) stated that as he was driving by when he noticed the female sitting on the ground with the male over her and he punched her in the face," the responding officer wrote.

But as he took Stratton into custody, he found him bleeding from his face.

The duo told police they had dropped off a friend in Amarillo, Texas, as they were headed toward California. 

Both of them appeared to have been drinking, according to the report – but each denied having been behind the wheel.

Nikki Alcaraz has bruises on her face and arm

The Cheatham County Sheriff's Office in Tennessee released these undated images of Nikki Alcaraz showing bruises on her face and arm. She went missing from a cross-country road trip earlier this month after an alleged fight with her boyfriend in New Mexico. (Cheatham County Sheriff's Office)

"It was determined that both parties were mutual combatants while traveling down the interstate," the responding deputy wrote. "The bruise on Ms. Alcaraz's arms came from Mr. Stratton holding her down to avoid being hit."

Police split them up, and the following day, Alcaraz showed up to retrieve her vehicle in the company of another man, according to the incident report.

Alcaraz, also known as Nikki Cunningham, last spoke with family via text on May 8, according to the Cheatham County Sheriff's Office.

Steven Tyler Stratton sticking his tongue out wearing sunglasses

Steven Tyler Stratton seen in November. 

The couple was headed from Ashland City to Orange County, California in Alcaraz's black 2013 Jeep Wrangler, authorities said. The license plate is BGL3539, and she has a bumper sticker reading "Mama Tried" or "Momma Tired."

Due to a history of domestic violence, Alcaraz may be in danger, according to the sheriff's office.

Earlier this month in New Mexico, they allegedly got in a fight, but no one was arrested. Police posted images showing Alcaraz with a black eye and a large bruise on her arm.

She last made contact with her family on May 8 – but over Memorial Day Weekend appeared on surveillance video at a Walmart store, where she sold her cellphone at an ecoATM kiosk, according to the Nashville-based WKRN-TV.

Despite the sighting, police are still looking to locate her, prosecutors told the station.

Black Jeep Wrangler with mud splashed on sides

Nikki Alcaraz's black 2013 Jeep Wrangler. (Cheatham County Sheriff's Office)

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Alcaraz is 5 feet, 6 inches tall and weighs about 160 pounds. She has a large tattoo across her chest, a piercing in her upper lip and dark hair.

Her ex-husband, Evan Cunningham, wrote on Facebook that there was also an unconfirmed sighting of her walking down a California highway after the Walmart appearance.

Alcaraz and Stratton had a third traveling companion whom they ditched in Texas, he wrote.

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Anyone with information on Alcaraz or Stratton's whereabouts is asked to call the Moriarty Police Department at 505-832-6060.

The case has drawn comparisons to the murder of Gabby Petito, who was killed in Wyoming during a cross-country "van life" road trip with former fiancé Brian Laundrie, just two weeks after the couple was involved in a public domestic violence incident in Utah.