A Gauteng man is under police guard in hospital after he was arrested for allegedly setting his girlfriend alight after dousing her with paraffin last week.The 42-year-old girlfriend, Primrose Mahlangu, died as a result of her injuries on Sunday morning.Kagiso police launched a manhunt for the man earlier on Monday afternoon who, according to spokesperson Captain Solomon Sibiya, was well-known.By 15:00 on Monday afternoon, the man was arrested at the hospital where he was being treated. He had burn injuries to his chest.Initially, the police said the man had used boiling water to burn the woman, but on Tuesday morning, corroborated the family's version - that the man used paraffin and set her alight. A family member, who asked not to be named, told News24 that the couple had been together for about three years.The family was shocked to hear the allegations."She was more outspoken. He was the quiet guy. No one expected this from him," said the family member.The family member said Mahlangu's mother coincidentally ran into the man at the hospital while he was being treated.Sibiya said the man would remain under police guard until he was well enough to appear in court. *An earlier version of this story stated that the suspect used boiling water to burn Mahlangu, as per the police's information. The police have since confirmed that the man set the woman alight using paraffin.