New York: Olympic 400m relay gold medallist Alvin Harrison has been banned for four years after he admitted taking a variety of performance-enhancing drugs. The USADA said on Tuesday that the evidence against Harrison constituted a so-called ?non-analytical positive? as he did not fail a drugs test.

?Harrison admitted to using numerous undetectable performance-enhancing drugs including anabolic steroids known as ?the clear? and ?the cream?, insulin, EPO, growth hormone and modafinil,? USADA said in a statement.

Harrison won 4x400m relay gold medals at the 2000 Sydney and 1996 Atlanta Olympics, and also two silvers in the 400 metres. The ban effectively ends the 30-year-old's career.

Three of the Sydney relay squad have either failed tests or been banned for doping, including Alvin?s twin brother Calvin. ?In addition to his suspension, which began on October 18 2004, Harrison forfeits all his competitive results and winnings since February 1, 2001,? the USADA statement said. Calvin was suspended for two years for a second doping violation involving modafinil in August 2004.

Scribe stabbed

Meanwhile in Athens, attackers in motorcycle helmets stabbed and beat a top Greek sports journalist who is a key witness into scandals involving the Athens Olympics, in what his newspaper called an assassination attempt on Tuesday.

Police said Filippos Sirigos, sports editor at major daily newspaper Eleftherotypia, was stabbed multiple times and beaten with crowbars in central Athens on Monday afternoon by at least two assailants as he left a weekly radio show he hosts.

Sirigos has given evidence against sprinters Costas Kenteris and Katerina Thanou, who were favourites to win medals in Athens before their shock withdrawal. (Reuters)