An Austrian court on Thursday acquitted the founder of the Blackwater private security firm and four others, finding no evidence they modified and exported two aircraft for military use, one of their lawyers said.
Erik Prince and four other men went on trial last month at a regional court outside of Vienna, accused of modifying two planes "for combat use" and flying them to South Sudan and Bulgaria.
The five defendants -- charged with violating the War Materials Act -- were all acquitted, lawyer Oliver Felfernig said, adding the judge found the two aircraft had not been modified for combat use.
"This has nothing to do with war material, or even dual use... There is nothing there," Felfernig told AFP.
Prince, a former Navy SEAL, drew infamy as the head of Blackwater, whose contractors were accused of killing unarmed Iraqi civilians in Baghdad in 2007.
Four who were convicted were pardoned by then US president Donald Trump in 2020.
Prosecutors can appeal Thursday's verdict. If found guilty, the defendants would have faced up to three years in prison.
Prince -- the brother of the former US education secretary Betsy DeVos -- worked with company Airborne Technologies, based in Wiener Neustadt, outside of Vienna, which modified the agricultural planes.
Prosecutors said they fortified the cockpit and installed a special camera, as well as hard points where "weapons could be attached", among other changes.
The defence refuted the planes were adapted for military use, saying they did not qualify as war material.
One of the two planes was exported in 2014 and flown to South Sudan. The second was sent in 2015 to EU member Bulgaria.
On trial together with Prince, 54, was an Australian pilot, who flew the planes out of Austria, as well as two Airborne Technologies executives and another pilot who allegedly acted as a consultant.
In a separate case, UN investigators in 2021 found that Prince violated a United Nations arms embargo on Libya, according to a report detailed by US media.
The report said that Prince deployed a force of foreign mercenaries and weapons to military strongman Khalifa Haftar, who has fought to overthrow the UN-backed Libyan government, in 2019.
Prince has denied the accusation.
Blackwater was renamed Xe in 2009 and became Academi two years later.