Adam Aviles Jr. was with his on-and-off again girlfriend and mother of their children, Katie Ferguson, when she disappeared during a cross-country trip
Missing Wyoming mom Katie Ferguson's family talks about her 'goofiness' and disturbing evidence
Nicole Ferguson, Katie's sister, and Angela Ferguson, Katie's stepmom, talk to Fox News Digital about the unnerving missing persons case.
The father of a missing woman's children is a "suspect in a homicide," and could face charges in another jurisdiction, according to federal court documents.
The four distressing words stuck out among the dozen-plus pages of court filings in Adam Aviles Jr.'s federal gun case, which included details of the cross-country trip he took with Katie Ferguson and their two young kids in October.
At some point during the week-long trip between Alabama and Wyoming, Ferguson vanished, and Aviles Jr. returned to Cody, Wyoming, without her.
The court documents filed last week were the first mention of a homicide, although Ferguson wasn't specifically named as the victim, and the first time Aviles Jr. was officially labeled as a suspect.
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Katie Ferguson, pictured here with her daughter and ex-boyfriend Adam Aviles, hasn't been seen since October. (Facebook)
The Park County Sheriff's Office in Wyoming, which is the lead investigative agency searching for Ferguson, told Fox News Digital on Monday that technically Ferguson is still considered a missing person because they don't have her body.
But investigators "have lots of evidence that she was injured," the Park County Sheriff's Office said, and law enforcement has a "working theory" that they're investigating.
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The sheriff's office couldn't discuss details of how Ferguson was injured or a potential motive at this point.
They tracked their movements using traffic stops in Colorado, Texas and Arkansas, which were outlined in federal court documents, but the multi-state component complicates efforts to find Ferguson or her body.
Katie Ferguson's family believes the 33-year-old mom of two died during a cross-country trip with her ex-boyfriend, who's facing federal gun charge. (Family handout)
Adam Aviles Jr. was originally arrested on less significant drug charges to hold him until the federal prosecutor officially charged him with a more significant crime. (Cody Police Department)
The criminal complaint against Aviles Jr. narrowed down a potential timeline to Oct. 5-9 and shrunk the approximately 2,000-mile road trip from Alabama to Wyoming to a stretch from Trumann, Arkansas, to Texas.
Ferguson was last seen during a police stop in Trumann around Oct. 5 in Aviles Jr.'s 1999 Durango, according to the court documents, which noted there "was no projectile hole in the passenger side door."
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On Oct. 9, Aviles Jr. was pulled over by Texas State Patrol, which was when law enforcement found a "projectile hole" in the passenger side door, and Katie wasn't in the car, according to the criminal complaint.
He was pulled over again in Colorado, and he was the only adult in the car, according to court documents.
That's still a huge geographical route to cover, and it's difficult to narrow down which areas in those states are most relevant, according to the Park County Sheriff's Office.
Law enforcement seen going through Katie Ferguson's ex-boyfriend's truck, where they allegedly found unnerving evidence, including blood, according to court documents. (Family handout)
Investigators asked the public — especially in those three states — to look through their security cameras, doorbell cameras and call with tips or information about potential sightings of the couple to 307-527-8700.
Aviles Jr.'s lawyer did not return Fox News Digital's request for comment.
The details about Aviles Jr. being a "suspect in a homicide" were revealed in last week's motion to extend his trial date, which was originally scheduled for Jan. 22, so the defense has time to gather all the facts in Ferguson's "homicide."
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"Defendant is requesting discovery regarding that case, which is expected to continue to be provided for several weeks as the investigation in that matter is in the initial stages," Aviles Jr.'s lawyer wrote in the motion.
"Further, Mr. Aviles may be facing additional charges in another jurisdiction, and it is crucial that defense counsel and Mr. Aviles are fully informed as to the extent and circumstances of the underlying allegations and the effect that a conviction or plea may have in that case."
Aviles Jr. was charged with being a felon in possession of ammunition. He pleaded not guilty.
The motion was granted to delay vacate the originally scheduled trial. A new date hasn't been set.
Chris Eberhart is a crime and US news reporter for Fox News Digital. Email tips to
