VATICAN CITY — It's one of the few parts of the Vatican readily accessible to the public: a small office, steps inside the city-state's border, where Catholics can purchase certificates of papal blessings for special personal occasions. Throughout a typical morning, customers stream up to the counter, ordering prayers for baptisms and anniversaries, giving their credit cards to nuns behind plexiglass.

Then, just before lunchtime, another worker emerges from a backroom, wearing a black sweater and clerical collar.

It’s Monsignor Carlo Capella, the Vatican’s only prisoner, finishing his morning shift.

For years, the Vatican’s justice system has been equal parts limited and obscure. The church has tended to emphasize spiritual penitence over penitentiaries. The city-state has just three prison cells. Its tribunal has rarely held criminal trials. And even when there is a high-profile conviction — like Capella’s, in 2018, with a five-year sentence for possessing and sharing child pornography — little is known about what comes next.

Capella’s daytime work-release program, previously unreported, was observed by The Washington Post and confirmed by his lawyer, who said the unpaid office job was aimed at his “rehabilitation.”

“As for the rest, it’s like a normal penitentiary situation,” said Capella’s lawyer, Roberto Borgo­gno. “There’s just no risk of riots.”

But long criticized for shielding its own, the Vatican is suddenly conducting trials at a frequency without precedent in the near-century since its creation as an independent city-state.

Its first sex abuse trial ended last week, absolving two priests — a decision that will be appealed.

A much larger-scale case is just starting, examining the potential financial crimes of 10 people, including Cardinal Angelo Becciu, involved in a Vatican mega-investment in a London luxury property. Lawyers in that case are arguing that Vatican prosecutors badly overreached, while committing procedural violations. The trial will probably drag on for months, if not longer.

But the very existence of that trial and others speaks to broader changes — some made under outside pressure — that have increased the possibility of prosecution inside the city-state.

The Vatican has been pushed to join more international agreements and, since adopting the euro, to apply tighter financial rules, including against money laundering. Pope Francis has also issued a series of orders on transparency and the handling of public contracts, expanding the Vatican’s powers in criminal matters while lifting certain statute-of-limitations measures.

Months into his pontificate, Francis decreed that even Holy See diplomats stationed abroad could face trial in the city-state’s courts. That determination eventually led to the trial of Capella, a priest-diplomat who had been stationed in Washington shortly before his indictment.

“We now have a lot of norms and rules that we didn’t have before,” Monsignor Juan Ignacio Arrieta, secretary of the Pontifical Council for Legislative Texts, said during an interview in a meeting room overlooking St. Peter’s Square.

The detention center itself is tucked away in a corner of the city-state’s 110-acre territory, away from the tourist traffic, in a wing of the barracks belonging to the Vatican’s police and security force. According to lawyers and people who have seen the area, each cell has its own toilet, as well as an immovable iron bed and a table anchored to the wall. The windows have bars but the glass can be opened. Several people noted that the food was good.

The facility can be used both as a jail, for pretrial detention, and as a prison for convicts. The Vatican is allowed to transfer criminals to Italy; indeed, after one of the highest-profile crimes committed in Vatican territory, the attempted assassination of John Paul II in 1981, the shooter served his sentence in an Italian prison.

But in other cases, the Vatican has kept its offenders in-house — including two people convicted in separate document-leaking incidents, whom the church worried might represent a security risk.

Before Capella, those leakers had been the Vatican jail’s most famous residents. One was a Spanish priest, Lucio Vallejo Balda, sentenced for passing documents to journalists, and granted clemency by Francis in 2016, halfway through an 18-month prison term. The other was Paolo Gabriele, a former butler for Pope Benedict XVI.

Gabriele had been such a fixture that he’d even hold the umbrella for the pontiff when it rained. Once accused, he said he had been trying to protect his boss, hoping to shed light on corruption and other nefarious activity, by stealing documents from the apostolic palace. But his leaks ended up triggering a major scandal, puncturing the Vatican’s reputation for airtight secrecy, and were seen as a possible component in Benedict’s ultimate decision to step down.

Gabriele spent time in a Vatican cell after his arrest and for two months of an 18-month sentence — before Benedict showed up for a visit and said he was pardoning him. In sparse accounts, the former butler portrayed the life of a Vatican prisoner as harsh. He said that while on trial, he was put in a room so small he couldn’t fully stretch his arms. He said the light was on constantly. Initially, “even a pillow was denied me,” he said.

Others familiar with the facility tell a different story.

“It was a luxurious prison,” said Ambra Giovene, the lawyer for Gianluigi Torzi, one of the 10 facing charges in the ongoing trial. She said the comforts were deliberate, as a way to make Torzi cooperative.

Torzi was temporarily detained for 10 days last year after being interrogated and then arrested. (He exchanged a hello with Capella in the barracks courtyard during his detention.)

None of the 10 now on trial are currently in detention.

Another lawyer, who represented Balda, said the priest’s experience was “very positive.”

“At the time, he was the only inmate, the poor guy. Whatever he asked, whatever he needed, [the guards] were always helpful,” said the lawyer, Emanuela Bellardini. “I didn’t have even one problem when I needed to meet him.”

Historians note that there was another era when the Catholic Church conducted justice on a far broader scale — in the open, and often brutally. During the centuries when the pope ruled territory across what is now Italy, one common punishment was a form of torture in which criminals were suspended by rope at their wrists, sometimes with weights attached. Some convicts were exiled to row aboard papal ships. Accused offenders from the nobility would be kept at Castel Sant’Angelo, but the benefits of their aristocratic status had limits; they could be tortured and executed on-site.

Today, Capella is held within Vatican territory that is many times smaller. His lawyer, who said Capella was unwilling to be interviewed, said his client is allowed to walk on a predetermined route within the city-state. But he can’t cross the border into Italy.

The Vatican “has the advantage of being very small, so control is granular,” Borgogno said. “Everyone knows who comes and goes. There’s no problem checking that he respects his limitations.”

The Vatican did not respond to a request for comment.

Capella, before his conviction, had said his behavior had been “repugnant” and blamed it on a period of crisis after moving to Washington, where he said he had little fulfilling work to do.

His new job, in the office that sells papal prayers and also deals with charity, was something Capella became eligible for only after he’d served a “sizable chunk” of his sentence, Borgogno said. Borgogno called it a role of “bureaucratic nature.”

He is just dealing with paperwork, Borgogno said.

But the “desk job” is important.

Without it, the Vatican’s lone prisoner would be in de facto solitary confinement.