A police official has told the South Gauteng High Court in Johannesburg that murder-accused Sandile Mantsoe admitted to him that he had killed his girlfriend Karabo Mokoena.Mantsoe allegedly disclosed that he had taken Mokoena to an open veld and burnt her, Captain Bhekisisa Freddy Mhlongo testified on Wednesday.He said, after his admission, he told Mantsoe to wait, "so I can get paper and pen, so I can write it down and sign that, but when I came back he changed his story".ALSO READ: Sandile Mantsoe often abused Karabo Mokoena, friend tells courtHe said Mantsoe had made the admission freely and voluntarily.Mantsoe is being charged with the premeditated murder of Mokoena, who was killed on April 28, 2017.Mokoena's charred remains were discovered in an open veld in Lyndhurst, Johannesburg.Mantsoe is also charged with assault with intent to do grievous bodily harm, for allegedly assaulting Mokoena on March 27, 2017.He has pleaded not guilty.His lawyer Victor Simelane said that Mantsoe had never confessed to killing Mokoena.'I didn’t force him to say anything'Mhlongo responded: "He denied when I said we must write the statement down.""I didn’t force him to say anything or to do what I wanted him to do. It is his right if he wants to keep quiet," Mhlongo said."When the accused told you the admission, what had you said to him?" Simelane asked Mhlongo."I had questioned him what was so heavy on him, which was in the dustbin that he dragged into the lift. It was because of my suspicions of what I had seen on the CCTV footage," Mhlongo replied.ALSO READ: Karabo Mokoena's alleged killer claims he's been assaulted in prison, court hearsThe court also heard testimony from Sergeant Matshidiso Maseko from the Diepkloof police station, who arrested Mantsoe soon after witnessing a wet carpet and blood stains in his apartment.Maseko said Mokoena's mother Keabetswe had opened a missing persons case on May 10, 2017, at the Diepkloof police station.She said that, on the same day, she was told that Mokoena's passport and identity document had been found at Mantsoe's apartment building.Maseko said that when she called Mantsoe, he had said he last saw Mokoena on April 27, 2017."He said that she was at his apartment and he accompanied her to get a taxi."'I asked him why the carpet was wet'Later that day, Maseko and other officials visited Mantsoe's Sandton apartment and asked the manager to view the CCTV footage. She said the footage showed that Mokoena was there at the stated time and that Mantsoe had accompanied her to get a taxi."At around 02:00 on the 28th of April, Karabo and accused went out of the lift and into the apartment."She said, on the same day, the accused had come out with a bin, adding that she did not see Mokoena leave the apartment building.ALSO READ: 'New developments' lead to postponement of Karabo Mokoena murder trialMaseko said that when Mantsoe came back to his apartment, he had given them permission to search it."I asked him why the carpet was wet, and he said he was selling the apartment, and that the estate [agent] and buyer were coming to the apartment."At the corner close to the window we found a small carpet and, when we moved it, we found bloodstains."She said she arrested Mantsoe after he denied knowing where Mokoena was.The matter continues.