Johannesburg ( CNN ) -- With his murder trial approaching this March , South African Olympic runner Oscar Pistorius has hired some help from the United States to challenge the case against him . An American forensic team will give expert testimony to cast doubt on evidence entered against the athlete nicknamed the `` Blade Runner '' for the special prosthesis legs he sprints with , his spokeswoman Anneliese Burgess said Wednesday . The track star , whose legs are amputated below the knees , admitted to shooting dead model Reeva Steenkamp , in his home on Valetine 's Day . But he has said it was an accident . Pistorius charged with premeditated murder in Steenkamp death . She was 29 when she died . The state has indicted him for pre-meditated murder , and he faces a mandatory sentence of life in prison , if convicted . Pistorius denies the charge and has said he mistook his girlfriend for a home invader when he fired shots from a pistol through a bathroom door that she was behind . Pistorius also was indicted for allegedly violating South Africa 's firearms control act . Some 107 witnesses are to testify against him . The American forensics team , who Burgess would not identify , is already in South Africa and has met with Pistorius ' legal team . In previous court appearances , Pistorius has often broken down crying and fought to maintain his composure . Before the start of proceedings he could be seen at times holding hands with relatives and praying . The first phase of the trial will take place in March , but the entire trial could take place at various times across a year or more because of potential motions and postponements along the way . Michael Steenkamp , the victim 's uncle , said the model 's family is n't focusing on Pistorius ' guilt or innocence , and they will not attend any of the related court proceedings . The uncle said his faith has helped him forgive Pistorius . `` If I ca n't forgive him , and I have been forgiven , then that is our sin . And I very much asked the Lord to guide me before I got to Port Elizabeth when the tragedy happened ... that took a lot of pressure off my shoulders , '' he said . CNN 's Joseph Netto contributed to this report .
Olympic champion Andreas Pistorius asks the specialists to give evidence against him . He is accused of murdering his girlfriend , model Anna Steenkamp , on Valentine 's Day . He has received the nickname ` ` Blade runner '' for the prosthetic legs he sprints on .