Handicap International claims that the training mine that exploded in Albania last month, causing the death of two trainees and the arrest of two charity staff, was supplied by the Albanian government's de-mining unit.
It is pinning its hopes on this defence to secure the release on bail of the two employees, UK mine clearance expert and project manager Graham Rees MBE and his Bosnian assistant Emin Durakovic.
Handicap International has lodged a formal appeal to the Albanian authorities for their release. The pair were arrested when they arrived in Albania last month after the 24 May explosion at a training centre for Albanian de-mining trainees. They are being held in custody having been charged with the use and transport of explosive materials.
The charity is demanding the release of the employees and is assisting with a technical investigation into the incident.
The French humanitarian agency said it only used defused ordnance in training exercises. Its UK director, Karl Blanchet, told Third Sector that the detonated mine was supplied to the charity by an official of the Albanian Mines Action Unit, a government organisation supported by the UN.
"Graham and Emin are still in police custody because the investigation is ongoing, and we don't know the results of the inquiry," said Blanchet.
"We have a few days to put in an appeal and we are working with our lawyers to secure their release."
The charity's team in Albania has halted de-mining activities to concentrate on supporting the injured and families of the victims of the blast. One of the critically injured has been evacuated to Italy for treatment.
"This is the first time in 10 years of mine clearance work we have had an accident," said Blanchet.
Handicap International works in 55 countries including Cambodia, Laos, Mozambique, Afghanistan, Democratic Republic of Congo, the Balkan states, and more recently in Iraq.