The lone holdout Manhattan juror in the 2015 Etan Patz murder trial is blasting Monday’s US Supreme Court decision to restore the conviction of Pedro Hernandez.

The former juror told The Post he remains convinced that the state’s case against Hernandez was built on “a house of cards” and that the real killer is still out there — decades after the 6-year-old boy’s tragic disappearance from a SoHo street in 1979.

“I’m just sad for the [supreme court] outcome and sad for what it means for Pedro’s Hernandez and his family, and also I think it’s not the right closure for New York, and it’s not the right closure for the Patz family,” said the ex-panelist, Adam Sirois.

Sirois was the only member of the jury at Hernandez’s first trial to refuse to find him guilty in the death of Etan, whose national-headline-grabbing disappearance led him to become one of the first missing children whose faces were put on milk cartons as part of a campaign in the ’80s.

After his 2015 mistrial, Hernandez, an 18-year-old bodega clerk at the time of Etan’s disappearance, was put on trial again in 2017 and found guilty.

Etan was officially declared dead in 2021, although his body was never found.

A federal appeals court then ended up tossing Hernandez’s 2017 conviction over a technicality involving jury instructions about the first of his many confessions — which included a chilling videotaped admission to fatally strangling the 6-year-old after luring him into the bodega basement with a promise of a soda.

That first confession, which was not videotaped, was made before Hernandez was arrested and read his Miranda rights, so it was tossed from evidence at his 2017 trial. When the jury asked during deliberations if that meant it should not consider any of Hernandez’s other confessions, the judge simply responded, “No.”

But the appeals court said the judge should have also made it clear to the jurors at the time that they needed to make up their own minds about Hernandez’s other confessions and for that reason, tossed his conviction.

The nation’s top court said in its ruling Monday that the lower court had no grounds to issue such a ruling, thus reinstating Hernandez’s conviction.

Sirois said the supreme court’s decision “seems very short and quick and presumptuous to me and not really a role for the supreme court to get involved in.”

He said the judge’s response to the jury’s “very good question” was “really poor.

“He should have given them the right to weigh their own decision on the validity of those subsequent confessions,” Sirois said.

“That could have swayed things the other way. It could have either resulted in a hung trial or perhaps even an acquittal.

“Everything boiled down to the validity of the confessions — the original confession, and then any subsequent confessions,” he said, calling those statements “the strongest piece of evidence” presented in trial.

He said he remembers listening to the prosecution try to “tie this thing together with a bow” but always felt the evidence was incredibly flimsy.

“If one of these pieces of evidence don’t fit exactly the way the police are telling the story, the entire house of cards just collapses,” Sirois explained, saying that the police built the case “around a story that they got Pedro to tell them under duress.

“Our jury deliberated for 18 days — and in the second trial, the jury deliberated for nine days… that doesn’t happen unless there’s a lot of doubt in the room,” Sirois said. 

He called the failure to pursue onetime suspect Jose Ramos’ connection to Patz’s disappearance as “screwed up,” citing a “chilling” video of Ramos admitting to dating the 6-year-old’s babysitter at the time.

“How they could not pursue him at that time,” Sirois said — a suspicion also held by Patz’s parents.

“I think that’s an important piece of the puzzle — that for whatever reason, the district attorneys at the time chose not to pursue that.”

But Manhattan District Attorney Alvin Bragg said Monday in hailing the latest ruling, “It is impossible to imagine the pain of losing a child, waiting so long for justice and having to race for more proceedings.

“Today the Supreme Court restored the murder conviction, and I hope the Patz family can breathe a little easier.”