Kaitlin Armstrong, the 34-year-old Texas woman accused of gunning down romantic rival and pro cyclist Anna Moriah "Mo" Wilson, is now the subject of a federal hold request as she sits in an Austin jail on $3.5 million bond, records show.

So even if she could post bail, she’d remain in custody on the detainer, former federal prosecutor Neama Rahmani told Fox News Digital Wednesday.

According to the Justice Department, federal detainers are formal notices informing a given jurisdiction that an inmate faces pending charges in another.

In Armstrong’s case, she is being held in Austin, Texas, on state charges of first-degree murder and theft of services. On the federal level, she’s been charged with unlawful flight to avoid prosecution after spending 43 days on the lam while named in a murder warrant.

TEXAS CYCLING MURDER SUSPECT KAITLIN ARMSTRONG ARRIVES BACK IN AUSTIN AFTER COSTA RICA ARREST

Kaitlin Armstrong split latest mugshot

Booking photos taken after Kaitlin Armstrong's extradition to the U.S. appear to show a change in her facial features.  (US Marshals, Travis County Sheriff's Office)

The former yoga instructor is accused of stalking and killing Wilson on May 11, according to an Austin murder warrant. Police alleged that her Jeep Grand Cherokee appeared on surveillance video near the crime scene moments before the slaying.

The Jeep showed up moments after Armstrong’s boyfriend, a 35-year-old fellow pro cyclist named Colin Strickland, dropped the 25-year-old Wilson off at her friend’s apartment in Austin, according to the warrant.

TEXAS MURDER SUSPECT KAITLIN ARMSTRONG THROUGH THE YEARS: LOVE TRIANGLE FUGITIVE SEEN IN DECADES-OLD PHOTOS

The two had gone swimming and out to dinner earlier that evening, police said, and had previously carried on a romantic relationship.

Moriah Wilson wearing a bicycle helmet and Kaitlin Armstrong

Left: victim Moriah "Mo" Wilson after a race. Right: A photo of suspect Kaitlin Armstrong released by the US Marshals. (The Wilson Family/US Marshals)

Strickland, who reportedly lost several sponsors in the aftermath of the shooting, updated his Instagram bio Wednesday to read, "I used to ride bikes, now not so much."

He has declined multiple Fox News Digital requests for comment, other than to say, "please f--- off."

He said in an interview with The Sun that he had a fling with Wilson in October 2021 during a break in his relationship with Armstrong – his live-in girlfriend. But they had since reconciled, and his relationship with Wilson was purely Platonic, he said.

According to police, over the winter he bought Armstrong the handgun that ballistic analysis would link to the crime in May.

Colin Strickland riding a bike wearing a helmet

Colin Strickland seen outside his Austin, Texas, home on June 17, 2022. (MEGA)

U.S. Marshals said last month, during a weeks-long manhunt for the fugitive Armstrong, that she sold her Jeep to a CarMax dealership less than a mile from her home days later for $12,200, well below market value.

She may have used that money as she allegedly dodged law enforcement, which obtained a warrant for her arrest on May 17.

Authorities have said she flew from Texas to New York, then from New Jersey to Costa Rica, where police found her in a hostel on the Pacific Ocean last week, according to the Marshals.

Photo collage of Kaitlin Armstrong with "captured" over her face and a picture showing her in custody

Kaitlin Armstrong altered her appearance in the 43 days she spent on the lam, according to authorities. (US Marshals/Harris County Sheriff's Office)

KAITLIN ARMSTRONG MANHUNT: NEW YORK CAMPSITE LINKED TO SUSPECT IN AUSTIN CYCLIST LOVE TRIANGLE SLAYING

She had a bandage on her face when law enforcement caught up with her at Don Jon’s Lodge in Santa Teresa Beach.

According to Deputy Marshal Brandon Filla, she claimed to have injured her face in a surfing accident. 

Booking photos taken after her extradition to the U.S. appear to show a change in her facial features. She had also cut her hair short and dyed it brown.

The Marshals Lone Star Fugitive Task Force and local law enforcement are expected to deliver a news briefing on the case Thursday afternoon.

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Armstrong’s next appearance at an Austin courthouse is scheduled for the morning of July 20. 

Her defense attorneys have said they will not be commenting on the case and asked for privacy for her family.

Fox News’ Rebecca Rosenberg and Sarah Rumpf contributed to this report.