BOSTON — Meet Glenroy “Trinny” Miller — the Mission Hill gangbanger who seemed to treat the federal criminal code like a to-do list.

Machineguns? Check.
Looting a credit union? Check.
Ripping off the U.S. Postal Service for half a million? Big check.

Now, the 29-year-old career criminal will spend nearly six years in federal prison after pleading guilty to a sprawling menu of charges that could double as a masterclass in how not to live on probation.

From prison cell to bank scam
Miller’s latest act started back in December 2019, just weeks into a three-year state sentence for gun crimes. Instead of using his prison time for reflection, prosecutors say he got busy plotting with longtime friend Nadaje Hendrix — then a loan officer at a federal credit union.

Together, the pair funneled out $134,000 in fraudulent loans, using stolen identities and even the names of Miller’s fellow inmates. It was an inside job with a twist: the inside was a prison cell.

Hendrix got eight months in 2024. Miller kept going.

From probation to postal heists
By the summer of 2023, Miller was out of prison and supposedly on the straight-and-narrow under state probation. Instead, he allegedly went straight to the blue USPS collection boxes.

Prosecutors say Miller and other Mission Hill crew members ran a classic “card cracking” operation — yanking checks out of mailboxes, chemically washing off the payee name, rewriting them to hand-picked “runners,” then draining the accounts before banks could blink.

The damage: between $250,000 and $550,000 in losses. The only thing more shredded than the checks? His probation terms.

From fraud to firepower
As if massive bank fraud and mail theft weren’t enough, Miller also peddled six firearms to a cooperating witness in 2023 — one equipped with a high-capacity magazine and a machinegun conversion device.

Prosecutors say Miller knew exactly who he was selling to: a convicted felon prohibited from owning a single bullet, let alone a fully tricked-out weapon.

The federal squeeze
By August 2024, the feds had had enough. Miller was indicted alongside eight other Mission Hill gang members and associates, capping an investigation involving the FBI, ATF, Postal Inspectors, Secret Service, Boston Police, Wellesley Police, and the Organized Crime Drug Enforcement Task Forces.

In court, prosecutors painted a picture of a man who simply didn’t know how to quit — from his prison scheming to his street-level gun running. Judge Nathaniel Gorton handed down the sentence: 71 months behind bars, plus three years of supervised release.

Miller’s criminal résumé

• Multiple gun convictions before age 30
• Credit union insider fraud
• Half-million-dollar USPS check-washing scheme
• Trafficking illegal firearms, including a machinegun

Federal agents called the case a blueprint for inter-agency cooperation. For Boston taxpayers, it’s a reminder that some gangbangers never clock out — until the feds slam the cell door.