June 30 UPDATE: Since the publication of this story, Kaitlin Armstrong was arrested in Costa Rica, according to U.S. Marshals. Read the latest update here.

(NewsNation) —The manhunt for Kaitlin Armstrong has reached six weeks. She is accused of murdering pro cyclist Moriah Wilson in a Texas love triangle,

According to a police affidavit, Wilson had met with the suspect’s boyfriend, fellow pro cyclist Colin Strickland, on May 11 — the night she was killed.

Wilson’s family believed she was not seeing anyone romantically. Still, investigators are looking at the case as a crime of passion.

Strickland, who said he briefly dated Wilson last fall, told police they went swimming and then to dinner. He says he then dropped her off at the home, where she was later found dead with multiple gunshot wounds.

Investigators say one minute after Wilson arrived home, security footage shows an SUV similar to Armstrong’s appearing to pull up outside. Detectives analyzed shell casings found at the scene of the killing against a gun belonging to Armstrong, writing in an affidavit, “The potential that the same firearm was involved is significant.”

On May 12, when officers confronted Armstrong with the video evidence, she reportedly provided no explanation and remained “very still and guarded.” Police later told her she was free to go.

Two days later, images showed Armstrong at an airport in Austin, Texas.

An anonymous tipster who police call credible said Armstrong discovered Strickland was romantically involved with Wilson and became “furious,” “shaking with anger” and wanted to “kill” her.

Police issued a warrant for Armstrong’s arrest May 17. U.S. marshals say Armstrong flew from Austin to Houston and then to New York City. On May 18, investigators believe Armstrong was dropped off at an airport in Newark, New Jersey. On May 25, another warrant for Armstrong was obtained for unlawful flight to avoid prosecution.

Investigators around the time of June 14 received tips that suggest Armstrong may be going by her sister’s name in New York state. On June 23, a black Jeep registered to Armstrong was found. It had been sold to a dealership in Austin on May 13. Police are now trying to follow her money trail.

Private investigator Jason Jenson has been following the case closely from the beginning. He worked with an expert to develop images showing what Armstrong may look like if she changed her appearance. The images are not from the U.S. marshals.

“The thing that really struck people the most about Kaitlin was her hair. So naturally, if she’s going to want to go undercover and not be detected in the public by anyone, she’s going to want to change that look. So that would be the first thing that she’ll want to do. In our prediction, since it was closer to a lighter color shade, you would want to go darker. Since it was long locks of hair, she’d likely go with no bangs, for that matter.

“So we pictured that if she’s going to try and conceal herself, she’s going to want to have bangs, or even introduced a bob look so that she completely transformed her life. As you can see from these images that my imaging expert put together, it’s remarkable how much you can actually change your appearance just from changing your hair,” Jensen said.

Armstrong is described as 5 feet, 8 inches tall, weighing around 125 pounds. Jensen suspects Armstrong may be posing as her sister Christine Armstrong.

“We know that on the 17th, her sister Christine Armstrong in the area of Livingston Manor all of a sudden decided that she needed a New York State driver’s license. So you know, if you’re on the run and you want to get a hair color, you go to your sister. We’re wondering if she changed her appearance and went and got this new Christine driver’s license and is running around the country using her sister’s name because that would be the perfect legal cover right? Instead of looking for Kaitlin Armstrong out of Texas, no one’s suspecting Christine or Elizabeth from New York,” Jensen said.

U.S. marshals will not confirm whether or not Armstrong has used the alias of her sister.

The search for Armstrong has been designated as a U.S. Marshals Service major case, which brings in additional manpower to help further the investigation.

There is also a major reward offered in the case of up to $21,000 for information leading to Armstrong’s arrest. Anyone with information on Armstrong’s whereabouts is urged to call the U.S. Marshals Service Communications Center at 800-336-0102.