BOGOTA, Colombia — In a cramped office in Colombia’s capital, where a single window looks onto a narrow air shaft, Pedro Lupera searches through scanned copies of contracts, invoices and bank wire instructions — all part of a trove of hundreds of thousands of pages of evidence smuggled out of Venezuela that he hopes will bring about the downfall of socialist President Nicolas Maduro.

Once one of Venezuela’s top anti-corruption prosecutors, Lupera left his home in Caracas five months ago with just $400 in cash and barely a change of clothes.

He ended up in neighboring Colombia, where he is one of a half-dozen exiled prosecutors and former aides to ousted Venezuelan chief prosecutor Luisa Ortega working with authorities in the U.S. and elsewhere to build cases against senior officials many blame for destroying their homeland.

Their efforts have yet to lead to any charges — a sign to some that Maduro has succeeded in destroying Venezuela’s justice system and that Ortega, in her rush to carve out a political future for herself, has promised more than she can deliver.

But for Lupera, like many of his colleagues, the crusade is deeply personal.

Once in charge of the country’s most politically explosive cases, he discovered that intelligence agents had cancelled his passport and ordered his arrest when he tried to travel to Brazil in July to collect evidence in a region-wide bribery scandal involving Brazilian construction giant Odebrecht. He managed to leave by using an alternative ID that permits Venezuelan citizens to cross into Colombia and then caught a flight to Brazil.

Two weeks later, he watched in shock as one of the prime targets of his investigations, Venezuelan United Socialist Party boss Diosdado Cabello, accused him on live TV of helping run a $6 million extortion ring.

“My ears began to get hot and red,” he said. “I felt completely impotent. Like my whole life had been destroyed.”

Ortega, a longtime admirer of the late Hugo Chavez, broke with the government this year over what she said was Venezuela’s descent into dictatorship when Maduro gutted the opposition-controlled National Assembly and created a parallel constitutional assembly to rule supreme.

For her outspoken views, she was removed in August and authorities accused her husband, socialist lawmaker German Ferrer, of orchestrating, with the help of Lupera, an extortion ring under her watch, something she denies. Venezuelan officials call Ortega’s anti-corruption activities an attempt to draw attention away from the investigations she and her husband face back home.

Far from being silenced, the maverick prosecutor has sharpened her attacks on Maduro’s government in frequent trips around Latin America and Europe.

Almost immediately after arriving in Bogota, Lupera and the others working to oust Maduro were welcomed by U.S. law enforcement agents and prosecutors pursuing charges against Venezuelan leaders, as well as Treasury Department officials running the Trump administration’s sanctions program against Venezuela.

But while the interaction with the Americans has been frequent, U.S. officials in private, as well as a former Ortega aide, cast doubt on how much evidence the prosecutors managed to collect. They also question Ortega’s willingness to cooperate, saying she may be more motivated by ambitions of becoming Venezuela’s first female president than revealing details of the corruption they believe she surely was aware of as the nation’s top law enforcement official for a decade, while pressing what many see as trumped-up charges against prominent government opponents.

Reflecting that hard-nosed view, the State Department denied Ortega’s request to travel to the U.S., according to two American officials, who spoke on condition of anonymity because they weren’t authorized to discuss visa cases. It didn’t help that in a 2015 speech to the National Assembly, she criticized the “powerful ones of the north” for their “colonial designs” on Venezuela’s oil wealth.

Ortega is adamant she has nothing to hide. She has some surprising defenders, too: among them Eligio Cedeno, a former banker targeted by Chavez who she helped jail in 2007. He has traveled to Bogota from Miami to meet with her on three occasions and said he is convinced she can play a key role in restoring Venezuela’s democracy.

“I’m not a witness, I’m the chief prosecutor,” Ortega told The Associated Press in an interview at her rented office in a leafy Bogota neighborhood. “I wasn’t present for these crimes. I have them documented.”

With few governments recognizing the Maduro loyalist who replaced her, Ortega and her team go about their work with an air of decorum that contrasts with their precarious position. On a recent AP visit to her office, she signed a letter on stationery embossed with the Venezuelan chief prosecutor’s office logo requesting information from Curacao as part of a money-laundering investigation. She also reviewed a brief she later filed with the International Criminal Court against Maduro alleging he oversaw crimes against humanity by Venezuela’s security forces.

In the months prior to Ortega’s flight, her aides said, they secretly digitalized and certified massive amounts of evidence — almost 150,000 pages worth in the Odebrecht case alone. They managed to sneak the information to Colombia for safekeeping before they fled themselves.

Even if the evidence can’t be used in a Venezuelan court, it’s a roadmap for foreign authorities looking into corruption and human rights abuses — transnational crimes that are the focus of what Ortega calls the world’s first prosecutor’s office in exile.

“We’re not going to just give up what we started,” said Zair Mundaray, formerly the No. 3 official at the prosecutors’ office and now coordinator of Ortega’s team. “Certainly in Venezuela there’s no way to correctly administer justice. … But as investigators we have the evidence, the proof and the expertise to take things where they need to go.”

Before leaving Venezuela, almost all of the ex-prosecutors had to spend weeks on the lam, moving between safe houses and switching burn phones frequently to evade around-the-clock surveillance. Several had their passports annulled. Mundaray’s house in Venezuela was raided.

After Lupera crossed the border into Colombia, he received a threatening text message and his top assistant was arrested for being part of the alleged extortion ring. The 43-year-old Lupera denies the charges, pointing out that the Swiss bank UBS didn’t even have a branch in the Bahamas at the time he and Ortega’s husband were accused of opening accounts there.

While in Bogota they all keep a high guard, none more so than Ortega, who moves around in two armored cars with a half-dozen bodyguards provided by Colombia’s government. Lupera recently dyed his hair after being warned by a former associate that Venezuelan intelligence agents were looking for him in Bogota.

“This at least allows me to feel a little more at ease,” he said while on a recent outing to look for hallacas — a typical Venezuelan cornmeal dish served around the holidays.

Another big challenge is making ends meet.

Several of the prosecutors share a small apartment in Bogota’s neglected downtown. Many have loved ones they have been unable to bring over. On Sundays, they go grocery shopping together at an outdoor market to stretch the $1,000 monthly stipend they receive, paid for by wealthy Venezuelan exiles. They don’t know how long the support will last.

Perhaps none has struggled as much as Lupera, who was hospitalized recently with hypertension and, without health insurance, is seeking treatment for five tumors found on his back. He says the hardships get to him at night, when he scans the news in Venezuela and thinks about all that he left behind.

But, he said, he wakes up every day determined to do whatever he can to shorten his exile.

“Each one of us, every morning, we hope that the work we do contributes a little grain of sand that will allow us to return to Venezuela,” Lupera said, trying not to choke up. “Not only return but hopefully change things so that we can have a new country we all deserve to live in.”


Joshua Goodman on Twitter: https://twitter.com/APjoshgoodman