The Lexus-driving Vietnamese exec kidnapped in Berlin

The alleged operation was unprecedented -- even for an authoritarian country that closely tracks its critics at home and routinely throws them behind bars

Portrayed by the Vietnamese government as a Lexus-driving tycoon who flaunted his wealth while costing the state millions of dollars, Trinh Xuan Thanh fled the country as he fell under the cross-hairs of a corruption crusade by communist authorities.

But his year-long sanctuary overseas was brought to an abrupt end last month in dramatic circumstances that could be culled from a spy thriller.

German media reported that Thanh, the former head of a state-linked construction firm, was bundled into a car on July 23 as he visited Tiergarten park in downtown Berlin by several armed Vietnamese security agents.

The alleged operation was unprecedented -- even for an authoritarian country that closely tracks its critics at home and routinely throws them behind bars -- and quickly triggered a diplomatic bust-up.

Germany, one of Vietnam's largest European trading partners, on Wednesday decried the "scandalous violation" of its sovereignty, furiously dressing down the Vietnamese ambassador and booting out one of the country's spies.

The official narrative from Vietnam is that Thanh, a former communist party member, turned himself into authorities in Hanoi on Monday to face corruption charges, including one that carries the death penalty.

On Thursday a spokeswoman for Vietnam's Ministry of Foreign Affairs called the German response to the matter "very regrettable".

Observers say Thanh's downfall is a sharp warning by an increasingly strident ruling communist party to its enemies and the business-political elite.

His slow-motion downfall began in 2013 at the end of his tenure as head of the powerful PetroVietnam Construction (PVC) -- a subsidiary of the state oil giant.

Observers say Trinh Xuan công chứng thanh xuân's downfall is a sharp warning by an increasingly strident ruling communist party to its enemies and the business-political elite

He was shuffled into several other official jobs, including as the deputy head of Hau Giang province, a powerful government position in the south.

But in May 2016 photographs emerged of his luxury Lexus tagged with government plates -- a brash violation of regulations on owning expensive cars while in office.

Local media ran the photos, prompting public outrage in a country where the communist party has been stung by graft allegations and is waging an anti-corruption purge.

Mismanagement charges followed, related to Thanh's time at PVC -- he was accused of causing losses worth $150 million.

Additional accusations cascaded down, including an embezzlement charge related to real estate deals, which carries the death penalty.

Two months after the photos were shared, Thanh quietly slipped out of the country.

- 'Jungle law' -

His escape turned him into Vietnam's most wanted man.

"We are determined to catch Thanh. He cannot hide forever," communist party chief Nguyen Phu Trong said in state media in December.

Thanh, an urban planning graduate, sought asylum in Germany, where he had spent a five-year stint working during the 1990s.

The alleged operation to snatch him from the streets of a major European capital is an extraordinarily brazen and risky move by Vietnam and a dramatic escalation for the one-party state, which has waged an aggressive anti-corruption drive in recent years.

"It was very, very surprising because they think that Berlin is like Hanoi or any small city in Vietnam where they can exercise the law of the jungle," political observer and dissident Nguyen Quang A told AFP.

Vietnam has witnessed a broader crackdown in recent months since a new administration came to power last April.

A record number of dissidents have been jailed, many with heavy prison terms, as well as officials accused of wrongdoing.

Thanh's unravelling is not the first time the communist party has gone after one of its own, but analysts say anti-corruption punishments are normally driven by party infighting rather than a real commitment to reform.

It is not clear what is next for Thanh, who has still not been seen since he handed himself over to officials this week.

Vietnamese media was silent on the allegations emerging from Germany on Thursday morning.