The International Press institute (IPI) today condemned the murder of a South Sudanese journalist whose body was found dumped at a farm last week some three months after he was kidnapped by armed men.

Six men reportedly abducted veteran journalist Isaac Vuni, former deputy director of South Sudan’s National Ministry of Information, and his brother in June.

Vuni was apparently killed shortly after the kidnapping and his body was found in the village of Kerepi along the Juba-Nimule road on Sept. 22. The whereabouts of his brother remain unknown.

IPI Director of Advocacy and Communications Steven M. Ellis said the case illustrated concerns over the safety of journalists in South Sudan, noting that at least six journalists have been killed in connection with their work since a civil war broke out in the country in December 2013.

“Our thoughts go out to Mr. Vuni’s family, friends and colleagues and we urge authorities to conduct a full, swift and transparent investigation into his killing,” he said. “We are extremely concerned about impunity for crimes against journalists amid the ongoing conflict and we urge the government to hold perpetrators of crimes against them accountable.”

According to South Sudan Liberty News, Vuni’s abductors were wearing the same uniform used by a battalion that provides bodyguards to President Salva Kiir. However, it is unclear whether the government was involved or whether the death was related to Vuni’s work. The journalist’s wife told Radio Tamazuj that her husband was involved in a land dispute prior to his death.

Vuni wrote for the Sudan Tribune, but reportedly had retired before his abduction in June. In 2009, he was arrested for reporting that the Sudan People’s Liberation Army and the South Sudanese government were implicated in a financial scandal. In 2011, he was detained during a crackdown on local journalists.

South Sudan’s civil war began in 2013 when Kiir accused his former deputy, Riek Machar, of attempting a coup. Fighting between forces loyal to the ruling Sudan People’s Liberation Movement (SPLM) party and the opposition have devastated the country ever since.

In January 2015, five journalists were killed in a convoy ambush as they were returning from a visit to victims of a previous attack. A military spokesman reportedly accused Uganda’s Lord Resistance Army, while the local governor blamed South Sudanese rebels.

Seven months later, journalist Peter Julius Moi was murdered in Juba after returning home from work. His death came days after President Kiir made public comments that many interpreted as a threat to kill journalists working against the government.

In July of this year, concerns increased when journalist John Gatluak was killed in an assault by South Sudanese soldiers on a Juba residential compound. Gatluak’s death was apparently due to his ethnicity and came amid a massacre of members of the Nuer tribe, to which he belonged.

The case garnered criticism of U.N. peacekeepers, who were accused of having ignored the attack in which a female aid worker was raped and other aid workers were assaulted.