Durban – A KwaZulu-Natal private investigator who, together with police, arrested a man accused of killing and burning the body of a 20-year-old woman, has described the suspect as "highly intelligent".Brad Nathanson said he took on the much publicised case of Siam Lee, who was kidnapped and killed, on a pro bono basis. "This was not about the money," he said.Nathanson spoke to News24 on Thursday after a man accused of kidnapping and burning Lee's body was apprehended in Assagay on Wednesday.Read: BREAKING - Arrest made in Siam Lee murder caseHe said the man appeared to be "highly intelligent". "He is a biochemist, speaks beautiful English and hardly the kind of guy you picture committing a crime of this nature."'Cocky and cheeky'Nathanson said he would "never forget" the man's demeanour."He is the complete opposite of what one might imagine. If I lined up 100 guys and ranked who could have killed her, he would be 100. He is so unassuming. He lives right here amongst everybody. In a good suburb."Nathanson said that the vehicle alleged to be used in Lee's kidnapping was found at the Assagay property in Hillcrest on Wednesday morning. The accused was arrested just hours later. "We had information that he was on the M13, and waited at his home. When he came in, he was nabbed."Nathanson said the man was "cocky and cheeky" during the arrest. "He didn't want cuffs on him initially."He said the car found would be taken for DNA analysis. "It also appears that the car was dinged up. He could have been in an accident in it. It was taken to Pinetown police station."Sources close to the investigation say the man is expected to appear in court on Friday. Police spokesperson Thulani Zwane confirmed that one arrest had been made. Lee's burnt body was found on a farm in New Hanover by a farmer just two days after her disappearance, although it was only identified by relatives five days later.After her disappearance, police put out an identikit of the man who was said to be driving a Mercedes-Benz Vito.