The South Sudan National Security Service (NSS) on Tuesday arrested a senior officer of the Sudan People's Liberation Movement/Army In Opposition (SPLM/A-IO) in Wau, Western Bahr el Ghazal State.
Brigadier General Oliver Vilario Osman's whereabouts remain unknown, the family said.
Farida Francis, his wife, told Radio Tamazuj Wednesday that Vilario left their house at 11 am and had not returned.
"A while after he left, I received a phone call that he had been arrested. He was taken by a group of people and we don't know his whereabouts yet," she said.
She added: "Since yesterday, Tuesday, his phone has been switched off, and we went to the headquarters of the security to find out his whereabouts, but they said they did not know his whereabouts."
However, SPLA-IO Brigadier General Charles Louis Juma in Wau told Radio Tamazuj that Gen. Oliver was arrested at midday by national security officers.
"We do not know the reason for his arrest. What happened is that a lieutenant named Fasco Michael, of the National Security, met Brigadier General Oliver, inside the forex bureau in the market, and the lieutenant took the brigadier to an unknown place," he said.
Gen. Louis condemned the arrest saying it is illegal.
"We are partners in the peace agreement, and they had to inform the party to which officer Oliver Osman belongs if there was a problem because he is a member of the movement. How Oliver was arrested is illegal and it affects the agreement because it is unethical," Charles said.
The SPLM/A-IO led by Dr. Riek Machar in a press statement last month voiced concerns of harassment of their members in Juba but did not elaborate.