Oscar Pistorius has been charged with the murder of his girlfriend after model Reeva Steenkamp was shot inside the Olympic athlete's home in South Africa.
Police said a 26-year-old male would appear in court later on Thursday.
Police in South Africa do not name suspects in crimes until they have appeared in court but police spokesperson Brigadier Denise Beukes said that Pistorius was at his home after the death of Steenkamp and "there is no other suspect involved."
Beukes said the suspect was undergoing blood alcohol and forensic tests and had made a request to be brought to court immediately.
Beukes said he would apply for bail, but the South African Police Service would oppose the application.
Beukes said there had been "previous incidents" at Pistorius' home.