Running: Boston MarathonRita Jeptoo was set to collect $500,000 at the New York Marathon on Sunday as the women’s World Marathon Majors series leader, but a positive drug test is putting that on hold.

The three-time Boston Marathon winner’s agent Federico Rosa told The Associated Press on Friday that Jeptoo tested positive for a banned substance in an out-of-competition doping test in Kenya on Sept. 25, two weeks before she won the Chicago Marathon on Oct. 12. Rosa would not identify what the substance was.

“We will legally go after the person or the people that convinced Rita to do this,” Rosa told The AP.

The International Association of Athletic Federations could not confirm or deny the test results, as “the case remains in the confidentiality phase.”

Jeptoo’s Chicago victory was her fourth straight major marathon win, which included back-to-back wins in Boston. The 33-year-old set Boston’s course record on April 21 with a time of 2:18:57.

Photo via Greg M. Cooper/USA TODAY Sports Images