Federal prosecutors have entered one of Oklahoma City’s most closely watched criminal cases by filing a new firearm charge against Benjamin Plank, the man accused in the 2022 ambush that killed an Oklahoma County sheriff’s deputy.
The federal case comes as Plank continues to face an ongoing legal battle in state court centered on his mental competency to stand trial.
Federal Complaint Focuses on Drug-Related Gun Possession
According to a criminal complaint filed in U.S. District Court, investigators allege that Plank admitted to being a long-term drug user and told authorities he had used methamphetamine on the morning of the shooting in August 2022.
Court documents state officers discovered:
- Glass pipes testing positive for methamphetamine and marijuana
- Numerous rounds of ammunition
- A firearm allegedly possessed while unlawfully using controlled substances
Federal prosecutors are now charging Plank under 18 U.S.C. § 922, which makes it illegal for unlawful drug users to possess firearms under federal law.
2022 Ambush Killed Deputy and Injured Another
Investigators say the shooting happened on August 22, 2022, when Oklahoma County deputies arrived at a southwest Oklahoma City home to serve an eviction notice.
According to earlier reports:
- Bobby Swartz was fatally shot
- Deputy Mark Johns was critically injured
Authorities allege the suspect then fled in a pickup truck towing a boat before being arrested outside a gate at Tinker Air Force Base.
Competency Dispute Delayed State Murder Case
The state prosecution against Plank has faced repeated delays because of questions surrounding his mental competency.
In 2025, an Oklahoma judge ruled Plank incompetent to stand trial after doctors reported:
- Persistent delusions
- Refusal to take medication
- Failure to make progress toward competency restoration
That decision temporarily dismissed the criminal case and shifted proceedings toward civil commitment.
Murder Charges Refiled Under New Oklahoma Law
State prosecutors later revived the case in January 2026, refiling:
- First-degree murder charges
- Shooting-related charges
The refiling was made possible by a new Oklahoma law that pauses the competency restoration timeline when a defendant refuses court-ordered medication.
Federal and State Cases Can Move Simultaneously
Legal experts note that both federal and state prosecutors can pursue separate charges connected to the same alleged conduct under the “dual sovereignty” doctrine.
That means:
- The federal firearm case
- The Oklahoma County murder prosecution
can proceed at the same time in separate courts.
Federal proceedings may now include:
- Initial appearances
- Detention hearings
- Discovery filings
while the state competency battle continues independently.
Summary Table
| Case Detail | Information |
|---|---|
| Defendant | Benjamin Plank |
| Federal Charge | Drug-user in possession of firearm |
| Incident Date | August 22, 2022 |
| Victim Killed | Sgt. Bobby Swartz |
| Deputy Injured | Mark Johns |
| Location | Southwest Oklahoma City |
| Federal Law Cited | 18 U.S.C. § 922 |
| State Case Status | Refiled after competency dispute |
The new federal gun charge against Benjamin Plank adds another major layer to a case that has already drawn years of public attention in Oklahoma. With both federal and state cases now active, courts will continue sorting through complex legal questions involving mental competency, firearm laws, and the deadly ambush that claimed the life of Sgt. Bobby Swartz.
