JUBA, Sudan (Reuters) - A minister in the government of South Sudan was shot dead inside his ministry on Wednesday, days after referendum results confirmed the region will become Africas newest independent state, the regions army said. South Sudans Interior Minister Gier Chouang Aloung said the attacker was the ministers brother in law. We want to make very clear there is no political motive whatsoever...it is a family issue... he was killed by his own brother-in-law. South Sudans army spokesman Philip Aguer said the Minister of Rural Development and Cooperatives, Jimmy Lemi, was shot dead inside the ministry in the heart of the regions capital Juba. (The attacker) also killed a guard at the door of the ministry, he said. Aguer said the attacker was under arrest. He had earlier said that the man had committed suicide. Officials said Lemi was a former member of the National Congress Party which dominates the north, who had defected to the souths ruling Sudan Peoples Liberation Movement ahead of April 2010 elections. Security forces had cleared away hundreds of onlookers from around the ministry. A government car with a window smashed was parked inside the building compound. We...saw a man taking a gun out of the car - he ran inside and we heard three or four shots, said one witness. An ambulance moved slowly away from the scene in a funeral procession, followed by dozens of wailing mourners. No motive was immediately clear for the attack, which underlines insecurity and the spread of arms in the region. Final results of a referendum on independence confirmed on Monday that South Sudan will become the worlds newest state on July 9. The region waged a decades-long civil war with Sudans north which ended with a peace deal six years ago. Violence in the south remains persistent since the end of the north-south civil war. An estimated 3,000 people were killed in ethnic battles and tit-for-tat cattle raids in 2009 alone, although clashes had subsided ahead of the January referendum.