The launch of Ukraine's new police patrol force last year sparked an internet craze of citizens posting selfies with newly recruited officers.
Their popularity stemmed not from their uniforms, body cameras and tablets, but the fact they did not demand bribes.
The most visibly successful reform to have emerged from the pro-European Maidan protests in 2014 is now under threat, serving and former law enforcement officials say, accusing vested interests of seeking to obstruct and discredit the force.
Vladyslav Vlasiuk, a lawyer by training who rose through patrol police ranks to become Chief of Staff of the National Police, quit in March, "exhausted" by the pushback against change, he told Reuters in his first media interview since.
The experience he described shows how fragile Ukraine's progress in transforming itself into a Western-facing free market democracy could prove to be.
The police reform, possibly for the first time in the former Soviet republic's history, "showed international partners that we in Ukraine are actually able to carry out some reforms," Vlasiuk said.
Before Maidan, police "would always do what the prosecutors say. Then it changed," he said. "The National Police positioned itself as a separate and equal law enforcement power. Prosecutors did not like it."
"We are seeing the prosecution service chasing patrol officers for wrongdoings. There is now a tension which is blocking the reform of the national police."
Deputy minister quits
In Ukraine, prosecutors have the power to launch investigations into public servants suspected of wrongdoing – a power which police officers say is being abused.
"When you are working within any public service in Ukraine, you have to be ready to deal with a lot of inspections, a lot of [expletive], a lot of irrelevant regulations," Vlasiuk said.
"And the prosecution is a controlling organ which can punish you for, in their opinion, improper actions," he said.
The General Prosecutor's office did not provide immediate comment when asked about the allegations.
The United States and European Union, which are helping to fund a $40 billion aid-for-reform program for Ukraine, have repeatedly called for a clean-up of the General Prosecutor's office, which they see as a key obstacle to fighting corruption.
Several high-profile reformers have been sacked from the government and prosecution service or resigned in frustration.
First Deputy Interior Minister Eka Zguladze has also quit, to take on an advisory role in the ministry. Her resignation statement on Wednesday gave no reason but contained a warning over the fate of reforms.
"I want to emphasize that these islands of success will drown in the ocean of corruption, nihilism, the bureaucracy, if we do not build bridges between them, creating a continent," she said. "And if in Ukraine we do not have the strength to go forward, the door, that we just opened, may close forever."
The system strikes back
With the help of U.S. money and training, and headed by a former Georgian minister, the new police force was set up as part of a root-and-branch reform to weed out endemic corruption.
The new patrol section was launched in July and incorporated into a revamped National Police force. The patrol officers seemed to be everything those dreaming of a new Ukraine after Maidan hoped: committed, trustworthy, less susceptible to bribes and not afraid to go after the rich and the powerful.
Drawn from all walks of life, they carried smart tablets as well as body cameras to make police work transparent. In a sign of changing times, Energy Minister Ihor Nasalik announced on Friday he'd been given a parking fine - and willingly paid.
Vlasiuk, 27, was part of a new generation of Young Turks entering public service after Maidan. He is in the process of setting up an NGO to provide legal assistance to officers and burnish the police's image nationally.
His former boss, Khatia Dekanoidze, a Georgian technocrat in charge of the National Police, described in a separate interview cases of vested interests undermining change.
An initiative to fire corrupt or incompetent officers by vetting them in a "reattestation" process has led to hundreds of lawsuits by sacked officers, some of whom got their jobs back.
Dekanoidze said judges were deliberately reinstating discredited officers for fear the judiciary could be next.
"This is a revenge of the old system, because the judiciary system, especially courts, they are part of the old system," Dekanoidze said.
There are other obstacles to reforms. The police budget is tight in a country at war with Russian-backed separatists and an economy that shrank by a tenth last year.
Keep calm and support police
An incident that has grown into a cause celebre for the police occurred on the night of Feb 7. A police car chased a speeding BMW through the streets of Kyiv, recorded on a black and white police camera in footage later broadcast on TV.
Starting with warning shots, three police officers fired a total of 34 bullets at the car during the course of a 40 minute chase, according to an Interior Ministry spokesman. Eventually, one of the bullets killed a 17-year-old passenger inside.
Prosecutors accused the officer of willful murder and abuse of authority; he is under house arrest while they investigate.
Police said the officer was trying to protect the public from a driver who was drunk. Their supporters protested in Kyiv holding banners saying "Keep Calm and Support Patrol Police" and the hashtag #savepolice appeared on Twitter.
Anton Gerashchenko, a lawmaker and member of the Interior Ministry council, said the case was an example of prosecutors seeking to show they remained in control by discrediting police.
Dekanoidze echoed that view. "Police reform is the only reform that is visible, that is a real reform for Ukrainians," she said. So when prosecutors went after those defending the lives of ordinary Ukrainians, "it looked like The Inquisition."
She added there were other cases when police had gone after illegal gambling rackets - only for prosecutors to open criminal cases against the officers.
A Western diplomat, who did not want to be identified by name, said the fight back by prosecutors showed reforms were starting to have a real impact.
"Prosecutors here are millionaires," the diplomat said. "They are powerful people who will fight to the very end to protect the resources vertical they created."
Much will hinge on the performance of the new General Prosecutor, Yuriy Lutsenko, a former interior minister whose appointment on Thursday raised eyebrows because he had no legal background.
Dekanoidze said she hopes prosecutors under Lutsenko will cooperate with the police. "Because... without a good and fair prosecution, police can't do anything."