Johannesburg - Doctors on Monday morning stopped all treatment for former top cop Piet Byleveld, who is in the Life Wilgeheuwel Hospital in Roodepoort.His stepdaughter, Virnalize Welthagen, told Netwerk24 "it is just a matter of time" before he dies. "It is not going well. He is not awake and we can see that he is very restless because he can’t breathe,” she said.Byleveld, who has been sedated since Sunday, has stage four cancer in both lungs - which has spread to his spine, adrenal gland and liver. Several ex-colleagues and relatives visited him at the weekend."There are fewer visitors today," said Welthagen, adding that Byleveld’s wife Elize has been at his bedside all the time."Elize is doing well under the circumstances.”Elize Swart, Byleveld’s sister, says the hospital is doing everything possible to keep him comfortable."He is suffering. We are all hoping and praying every day, but things don’t look good," Swart said.Byleveld – or Piet Byl, as he is also known – retired in 2010 after a career of 38 years with the police. He was involved in several high-profile cases, including that of Leigh Matthews, Sibille Zanner and Sheldean Human. He was also responsible for the arrest of serial killers Cedric Maake and Lazarus Mazingane.