STELLENBOSCH, South Africa (AP) — Chicago Marathon champion Rita Jeptoo failed a doping test in September, the Kenyan runner’s agent said Friday.

Federico Rosa told The Associated Press that Jeptoo tested positive for a banned substance in an out-of-competition test in Kenya weeks before she won a second straight Chicago Marathon title on Oct. 12.

READ MORE: Chicago Weather: Dry And Quiet Tuesday Night

“This is true,” Rosa said in a telephone interview.

Rosa said Jeptoo’s “A” sample had tested positive and they were waiting for her backup “B” sample to be tested. Rosa declined to name the substance.

Rosa said he had learned of the positive test “a few days ago.”

“We will legally go after the person or the people that convinced Rita to do this,” Rosa said, adding Jeptoo’s management had “nothing to do with” any doping. “I am sorry for Rita.”

Chicago Marathon executive director Carey Pinkowski released a statement but isn’t making any rulings at this point.

“We will wait for the International Association of Athletics Federations (IAAF) to release the final ruling in this matter before addressing the athlete’s standing with the Bank of America Chicago Marathon,” Pinkowski said.

“It is premature for us to provide additional comment at this point.

READ MORE: Riviera Country Club In Orland Park Ordered Closed; Couples Say They Put Down Money With Operator Who Turned Out To Be Convicted Scammer

“Our race has been and continues to be a strong advocate for strict anti-doping measures.”

The 33-year-old Jeptoo has won back-to-back titles at the both the Chicago and Boston Marathons and leads the World Marathon Majors series.

The series said earlier Friday that it had postponed Sunday’s awards ceremony because of the positive test.

“No athlete can win the World Marathon Majors Series title who has been in breach of IAAF anti-doping rules,” the series said.

The IAAF said in a statement that it was “not in position where it can confirm or deny” Jeptoo’s positive doping test.

“The case remains in the confidentiality phase,” the IAAF said, “although that should be lifted within the next week.”

Jeptoo’s failed doping test comes as Kenya is under close scrutiny for a recent spike in doping cases.

A report into doping in Kenya was released this month. The investigation found that the East African country has problems with athletes from a number of sports using banned substances.

MORE NEWS: Concert Venue Metro Requiring Proof Of COVID-19 Vaccination For All Events

Copyright 2014 by The Associated Press. Any commercial use or distribution without the express written consent of The Associated Press is strictly prohibited.