LONDON — Usain Bolt and his club teammates ran the fourth-fastest 400-meter relay time in history at the London Grand Prix today, shrugging off a developing doping probe involving Jamaican sprinters.

Bolt anchored the team that included fellow Jamaicans Yohan Blake and Mario Forsythe, plus Antigua's Daniel Bailey, representing the Kingston-based Racers Track Club. They won in 37.46 seconds.

"It was a good race, a good team effort," the triple Olympic champion and world record-holder said. "We executed it well."

At the end of a two-day meet overshadowed by speculation surrounding the Jamaican doping investigation, even the relay win had a dramatic twist.

The Racers TC team was initially disqualified because the 19-year-old Blake broke too quickly at the start of the second leg. However, the judges changed their minds and the quartet was reinstated within 30 minutes.

On Friday, Jamaica's new anti-doping organization said that four male sprinters and one female tested positive for an unidentified drug at their national championships last month. They have been asked if they want their backup samples tested.

"I don't know what is happening back home," said Bolt, who is not involved in the probe. "All I know is that we have to wait for the results of the second tests."

None of Jamaica's Olympic medalists from Beijing are implicated.

However, the country's anti-doping officials said all five were chosen in Jamaica's team for the world championships being held August 15-23 in Berlin.

The woman was identified Saturday as Sheri-Ann Brooks.

Brooks' manager Chris Mychasiw told The Associated Press that the athlete had been officially notified as being involved in the scandal.

The 26-year-old Brooks won the 100-meter Commonwealth Games title in Melbourne in 2006. In 2005 she was the NCAA college champion over 200 when running for Florida International University.

Blake, who ran a personal best 9.93 to finish third behind Bolt in Paris last week, declined to answer questions about the probe Saturday.