Relatives of a murdered Armenian army officer killed with an axe by an Azerbaijani counterpart on a NATO training program in Budapest are hoping the European Court of Human Rights will hand down rulings against Hungary and Azerbaijan on Tuesday, The Guardian reports.

Gurgen Margaryan was murdered in February 2004 by Ramil Safarov, while both men were attending a three-month Nato English-language training course in the Hungarian capital.

At Safarov’s subsequent trial, he said he was motivated by hatred for Armenia and Armenians, due to the war between the two countries. He was jailed for life by the Budapest court. However, in 2012 Hungary sent Safarov back to Azerbaijan to complete his sentence. On arrival, he was promptly pardoned, released and given a hero’s welcome.

“Though this heinous incident happened 16 years ago, it still remains alive in my memories,” said Hayk Makuchyan, another Armenian officer on the course, whom Safarov had also wanted to kill. He and Margaryan’s relatives are the claimants in the current ECHR case. They are not seeking financial compensation from either government.

“We have sought justice rather than compensation. What matters to us is the acknowledgment of the fact of grievous violations, putting an end to impunity and the prevention of hatred against Armenians,” said Makuchyan, in emailed comments.

Nazeli Vardanyan, the claimants’ lawyer, said although Margaryan’s family were struggling for money, they made it clear they did not want financial compensation. “They only want justice,” she said.

The Guardian reports that tens of thousands of people were killed in a war between Armenia and Azerbaijan in the early 1990s over the disputed territory of Nagorno-Karabakh. A ceasefire was agreed but there is still periodic fighting in the area. Since then, the two countries have had no diplomatic relations and there are no travel links between them.

The 2004 murder further increased tensions.

When Safarov arrived back in Baku in 2012, he was given an official pardon by the president, Ilham Aliyev, a promotion in rank, a free apartment and back pay for the eight years he had spent in a Hungarian jail. He is believed to still be in active service with the Azerbaijani army.

“Azerbaijan’s shameful act seriously endangers the security of the entire south Caucasus,” said the then president of Armenia, Serzh Sargsyan, shortly after Safarov was released. “Making a hero out of a criminal is unacceptable.”

“Ideally, we’d like the court to order him transferred back to Hungary or a third country, to complete his sentence, because in Azerbaijan he is treated as a hero,” said Vardanyan.

Philip Leach, the director of the European Human Rights Advocacy Centre, which is also representing the claimants, said the case covered new legal territory and the court ruling could have profound consequences for future cases of prisoner transfers.

“It’s quite common around the globe that people are pardoned or amnestied for political reasons, but when states issue amnesties or pardons, it is often in breach of their human rights obligations,” he said.

A report by the Hungarian ombudsman in 2012 found Hungary had not infringed any international norms, but nevertheless concluded that the Hungarian government “was not sufficiently prudent when it did not require any guarantee from Azerbaijan”.

The decision came shortly after Hungary’s prime minister, Viktor Orbán, had travelled to Baku. The Hungarian government denied allegations of impropriety in the case.

“With regards to Hungary I have conflicting feelings: gratitude to the judiciary of Hungary, which was strong enough to administer justice … [and] disappointment for the extradition of a murderer against court decisions and persistent risks of impunity,” said Makuchyan, who now works in Armenia’s defence ministry.