When a UPS Store owner in Southern California cracked open a suspicious package in 2014 and found three pounds of pure methamphetamine inside, her discovery sparked a police sting 1,800 miles away that netted the arrests of three Houma men.

Authorities said they also turned up $5,000 in cash and an AK-47 from what Terrebonne Parish Sheriff Jerry Larpenter described as a "huge" drug ring. A jury last year convicted two of the men, and the third awaits trial.

But a federal judge in New Orleans has left the prosecution in tatters, ruling that the UPS Store owner was acting as a government agent when she opened the package without a warrant, making it an illegal search.

In a 42-page ruling this month, U.S. District Judge Susie Morgan granted Philips Thompson, the man who sent the package, a new trial while agreeing to suppress the drug evidence against him.

Thompson's attorneys said he had faced a mandatory life prison sentence, thanks to a pair of prior convictions.

Morgan also agreed to suppress the same evidence against Kerry John Lirette Jr., who lived at the address in Houma listed on the meth package and who took it in.

Lirette's trial, previously scheduled for January, is now up in the air. After her ruling, Morgan agreed to postpone the trial date until April.

"It's pretty clear that everything from this case started and ended with that package," said attorney Sam Winston, who represents Thompson. "All of the evidence came from that package. Once you throw that out, there isn't anything left."

Akari Williams, the intended recipient of the meth package who was found guilty alongside Thompson, remains convicted. Morgan ruled that Williams' attorney failed to raise the issue soon enough. Even if he had, Williams was neither the sender nor the addressee for the package and "had no legitimate expectation of privacy in the package," Morgan wrote.

Williams, who was convicted of a drug conspiracy and possession with intent to distribute marijuana, awaits sentencing.

The latest decision from Morgan, who was nominated to the federal bench by President Barack Obama in 2011, reversed her own decision before last year's trial rejecting pleas to suppress the drug evidence that the UPS Store owner found.

In her new ruling, Morgan said she changed her view after hearing testimony from the UPS Store owner, Patricia Tarango, and detectives that suggested the San Bernardino County Sheriff's Department was well aware of her practice of opening suspicious packages without a warrant and had tacitly endorsed it for a decade.

Tarango had a written agreement with the agency to serve as an informant, and the agency paid her occasionally when her hunches proved right.

Former federal prosecutor Michael Magner, who also represents Thompson, called Morgan's ruling unusual. Few motions to suppress evidence are successful in federal court, Magner said, and rarer still does it happen after a trial.

Magner said the ruling makes it "essentially impossible" to retry his client.

Morgan granted motions to suppress the drug evidence that attorneys for Thompson and Lirette each had filed. Thomas Calogero, who represents Lirette, said, "We were prepared for trial and we expected Lirette to be acquitted, even if the evidence had not been excluded."

The U.S. Attorney's Office in New Orleans is weighing its options on the case and whether to appeal Morgan's ruling, an official said.

Alerted by California authorities, Terrebonne Parish deputies conducted a "controlled delivery" of the package to a house Williams owned on Grace Street in Houma.

Lirette collected the package and took it to Williams, his brother-in-law, before police made the bust.

At the time, Larpenter estimated the street value of the seized drugs at more than $200,000, according to local media reports.

Morgan declined to acquit Thompson outright but vacated his conviction and granted him a new trial, ruling that the May 27, 2014, package search, "and the fruits thereof, are suppressed and shall not be entered into evidence at his new trial."

She issued the same ruling over the evidence for Lirette's pending trial.

Winston described the ruling as "a victory for the Fourth Amendment," which guarantees "the right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures."

Follow John Simerman on Twitter, @johnsimerman.