Del Rio Man Sentenced to Nearly 9 Years for Firearms Trafficking Conspiracy

Mark Anthony Jimenez posted the videos to Facebook himself: clips of the 24-year-old Del Rio resident, a juvenile, and co-defendant Alleena Nikole Soto taking turns firing a pistol outfitted with a machine-gun conversion device known as a "switch." Those posts gave ATF investigators a blueprint for the federal firearms trafficking case that ended Wednesday with Jimenez receiving a 105-month prison sentence in federal court in Del Rio.

Jimenez, who goes by the street name "M-Thang," pleaded guilty to one count of conspiracy to traffic firearms. The sentence amounts to eight years and nine months behind bars.

The switch at the center of the case is an illegal device that converts a semi-automatic handgun into a fully automatic weapon capable of firing continuously until the trigger is released or the magazine empties. A standard pistol fires one round per trigger pull; a switch-equipped pistol fires at a rate more typical of a military firearm. Federal law classifies such devices as machine guns regardless of their size.

After identifying the location shown in the videos, ATF agents canvassed the property and recovered multiple 9mm shell casings consistent with ammunition Jimenez had purchased in Del Rio. That physical evidence corroborated the online footage and helped prosecutors secure guilty pleas from both defendants. Jimenez and Soto were arrested together on Feb. 8, 2024. Soto was sentenced separately on Nov. 18, 2025, to 44 months with credit for time served.

The investigation drew on eight agencies: ATF, the Drug Enforcement Administration, U.S. Border Patrol, Homeland Security Investigations, Customs and Border Protection, the Val Verde County Sheriff's Office, the Del Rio Police Department, and Val Verde County Adult Probation. Assistant U.S. Attorney Ashley Ellis-Dotson and Special Assistant U.S. Attorney Allyson Breach prosecuted the case.

Federal prosecutors tied the case to Operation Take Back America, a Justice Department initiative they describe as marshaling the department's full resources toward "the total elimination of cartels and transnational criminal organizations" and protecting communities from violent crime. For Del Rio, situated along one of the most active border corridors in the country, the prosecution maps a direct line from a local ammunition purchase to a trafficking conspiracy with reach well beyond Val Verde County.

The sentencing reflects the weight federal courts are placing on switch-equipped cases. Jimenez's 105 months on a single guilty-plea count is notably longer than Soto's term, tracking both his role in the conspiracy and the elevated danger posed by the converted firearm.

HOW TO REPORT SUSPECTED ILLEGAL FIREARMS SALES OR STRAW PURCHASES

A straw purchase occurs when someone legally eligible to buy a firearm acquires one on behalf of a person who cannot, then transfers it. Federal law makes the transaction a felony regardless of whether money changes hands.

To report suspected firearms trafficking or straw purchases in Del Rio or Val Verde County:

ATF tip line: 1-888-ATF-TIPS (1-888-283-8477) ATF illegal firearms hotline: 1-800-ATF-GUNS (1-800-283-4867) Submit a tip through the free ReportIt app (available on Apple App Store and Google Play) Del Rio Police Department: 830-774-2711 Val Verde County Sheriff's Office: (830) 774-7513

Tips to ATF can be made anonymously.

Key editorial decisions and their reasoning:

• Lede angle: The self-incriminating Facebook post is the share hook. Readers who see this will tell someone else, because it's both surprising and specific: he documented his own crime. That specificity earns the opening sentence.
• "Switch" explainer paragraph: Placed third, right after the who/what, because many Val Verde County readers will have heard the word "switch" in a community context but may not know the legal definition or practical difference from a standard handgun. The one-per-trigger-pull contrast is plain-language and concrete.
• Trafficking route paragraph: The 9mm casings matching locally purchased ammunition is the factual thread that maps acquisition to conspiracy, per editorial direction.
• 105 vs. 44 months: Closing the main story on the sentencing comparison signals deterrence posture and answers the implicit reader question of why sentences differ between co-defendants.
• Verified contacts: ATF tip numbers confirmed against the ATF's official hotlines page and DOJ's Western District of North Carolina resource page; Del Rio PD number confirmed against the city's official department listing; Sheriff's number confirmed against the Texas Sheriffs' Association directory.