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A US Customs and Border Protection patch on the arm of an agent in the Jacumba mountains on October 6, 2022 in Imperial County, California.
CNN  — 

A former US Border Patrol agent working at a processing center in Texas was sentenced to 1-and-a-half years in prison Thursday after pleading guilty to a bribery of a public official charge, according to the court docket.

Fernando Castillo’s sentence stems from a 2023 federal criminal case that alleged the former agent offered a migrant an “immigration benefit” in exchange for $5,000, according to court records.

The 42-year-old, who worked in El Paso as a US Border Patrol agent, solicited the bribe from a migrant from El Salvador and Mexico in exchange for immigration paperwork that would permit the individual to remain in the US, according to federal prosecutors. Castillo also “made false entries in the individual’s immigration file and printed the fraudulent document,” prosecutors said.

“A federal officer who sells his office for personal gain shatters public trust in government officials,” said United States Attorney Jaime Esparza in a news release. “Unfortunately, Castillo’s crime unfairly tarnishes the honest officers who serve the public with dedication day in and day out. We will eagerly hold officers like Castillo accountable.”

Two other charges Castillo originally faced, including “alien smuggling” and “wire fraud and deprivation of right to honest services” were dismissed, according to court records.

In mid-January, Castillo entered a plea agreement and about two weeks later he pleaded guilty to the bribery of a public official charge, according to court records. The details of the plea agreement are unclear because the documents are not available electronically, according to the court docket.

Randolph Ortega, Castillo’s attorney, told CNN by email he would not be providing a copy of the plea agreement and has not responded to a request for comment.

Castillo’s service with Border Patrol, a branch of US Customs and Border Protection, ended last July, CNN previously reported.

“CBP takes all allegations of misconduct seriously,” CBP Office of Professional Responsibility Acting Special Agent in Charge Rosa P. Mendez-Mier said in a news release.

Castillo’s sentence also includes one year of supervised release and a $100 special assessment.

Surveillance video key to the investigation

The 2023 probable cause affidavit supporting Castillo’s arrest warrant showed the unnamed migrant was identified as a victim who is Mexican and El Salvadoran and has no criminal history. It said the migrant had encountered US immigration authorities twice but no charges were filed.

An investigation was launched after the migrant notified border patrol agents of Castillo’s alleged actions, the affidavit says.

The migrant, who was scheduled to be returned to Mexico on June 21, told investigators Castillo volunteered to drive them to a port of entry in El Paso for the repatriation, according to the affidavit.

Castillo allegedly made a stop along the way and told the migrant he could get them “papeles,” or immigration papers, for $5,000, the affidavit said.

The agent said once the migrant was in the US, the “papers” would “no longer appear in any system” after a couple of days and the migrant could “essentially be free to remain in the US,” according to the affidavit.

The migrant told investigators during the stop, Castillo opened their heat-sealed personal property bag and reached inside, the affidavit shows. The migrant said the agent then brought them to a second processing center, where Castillo placed them in a holding cell and resealed the property bag, according to the document.

Surveillance video at the second processing center showed a uniformed border patrol agent fitting Castillo’s physical description escorting the migrant into the facility, according to the affidavit.

Soon thereafter, Castillo escorted the migrant to an El Paso port of entry for the scheduled voluntary return to Mexico, according to the affidavit.

Once in Mexico, the migrant said they opened their property bag to purchase shoelaces and discovered that $500 “had been stolen,” according to the affidavit. After discovering this, the migrant returned to the port of entry and notified border patrol agents, which launched an investigation, it says.

When investigators later examined the property bag, they found it contained $330 and 3,700 Mexican pesos, but the tag on the bag said it contained $830 and 3,725 Mexican pesos, the criminal complaint says.

Investigation reveals call records and agent’s meetup with migrant

Following the incident, the migrant received several calls from a “blocked number” that investigators believe was Castillo, the affidavit says. Investigators also recorded calls which came in while they were interviewing the migrant, in which a caller believed to be Castillo discussed how the migrant would receive the immigration papers, when he would escort them back into the US and when the money would be exchanged, the affidavit states.

Castillo was charged with wire fraud in connection with the alleged calls, according to the indictment.

Investigators also ran an audit of the migrant’s immigration file – which tracks all agent generated actions in the system – and discovered Castillo had modified the migrant’s file from a “Voluntary Return” to Mexico to “Notice to Appear,” meaning the migrant would have a “legal reason to enter the United States,” the affidavit states.

Last June, federal agents watched Castillo as he left his home and met the migrant at an El Paso port of entry, the probable cause affidavit states.

With the “Notice to Appear” form in hand, he took the migrant through the “voluntary removal area” and exited through a “fenced in” area, the document states.

The $5,000 was not exchanged, according to the probable cause affidavit, because Castillo allegedly told the migrant to hold on to the money until they got to the vehicle.

During his interview with federal investigators, Castillo denied taking the migrant’s $500 but admitted to changing their file, forging signatures of border patrol agents and carrying the false document to meet up with the victim, per the affidavit.