Three-time Olympic champion Marion Jones has asked for forgiveness after admitting that she lied about taking performance-enhancing drugs.Jones, the former golden girl of American athletics who won five medals at the Sydney Olympics in 2000 said she only had herself to blame.She faces jail after pleading guilty to lying to US government investigators in 2003 about her use of steroids and taking a banned substance known in sporting circles as 'the clear' because of its difficulty to detect.She also confirmed her retirement from athletics after admitting she lied to a federal investigator in November 2003 when he asked if she had used performance-enhancing drugs.Jones, 32, also pleaded guilty to a second count of lying to investigators about her association with a cheque-fraud conspiracy.After a court hearing in New York she said: "It is with a great amount of shame that I tell you I have betrayed your trust."Jones added: "Making these false statements to federal agents was incredibly stupid and I am fully responsible for my actions."I want you to know I have been dishonest. I have nobody to blame but myself. I have let them down, let myself down and let my country down."The International Olympic Committee has already opened an investigation into doping allegations against Jones in December 2004, and said it would step up its probe and move quickly to strip her of her medals.The IOC and other sports bodies can go back eight years to strip medals and nullify results.In Jones' case, that would include the 2000 Olympics, where she won gold in the 100m, 200m and 1,600m relay and bronze in the long jump and 400m relay.© Independent Television News Limited 2007. All rights reserved.