Boston marathon winner Rita Jeptoo has drugs ban extended to 2018

• Kenyan was initially banned from 2014-2016 after testing positive for EPO
• Jeptoo won Boston and Chicago marathons in 2013 and 2014.

The Kenyan marathon runner Rita Jeptoo has been banned for four years for a doping offence with “aggravating circumstances”, the court of arbitration for sport has announced.

Related: Rita Jeptoo’s two-year doping ban should be doubled, says IAAF

The 35-year-old tested positive for recombinant EPO (rEPO), an artificially produced hormone stimulating red blood cell growth, in a sample given prior to winning the 2014 Chicago marathon. She was disqualified from that race and given a two-year ban by Athletics Kenya for the offence, but the IAAF appealed to Cas seeking a longer sanction.

That appeal was upheld in Wednesday’s verdict from Cas, which read: “The panel found to its comfortable satisfaction that the athlete used rEPO over a period of time to enhance performance. The undisputed source of the rEPO found in her sample of 25 September 2014 was an injection given to her by a doctor. The athlete provided various differing accounts of the circumstances leading up to the injection and also regarding her relationship with that doctor.

“According to the applicable rules, the minimum period of ineligibility in this situation is a sanction of two years but can be increased to up to four years in the case of aggravating circumstances. The panel is comfortably satisfied that there are aggravating circumstances in the case at hand as it was obvious to the panel that the athlete used rEPO as part of a scheme or plan.”

The statement added: “The evidence for this includes her long relationship with the doctor in question, her multiple visits to see him, that her rEPO use was consistent with her competition calendar, that she hid the visits to the doctor in question from her manager and coach, as well as her deceptive and obstructive conduct throughout the proceedings.

“Weighing all the evidence, the panel is comfortably satisfied that the circumstances warrant a period of ineligibility of four years.”

Jeptoo’s results from 17 April 2014 have been disqualified, costing her victories in Chicago and in the same year’s Boston marathon, where she had set a course record of 2hr 18min 57sec. She won both those races in 2013, as well as the Boston title in 2006, and has further marathon wins to her name in Stockholm and Milan in 2004 along with half-marathons in Paris in 2006 and Lisbon the following year. Jeptoo also won a bronze medal over 20km at the 2006 IAAF world road-running championships. In addition to her extended ban the athlete has also been fined 15,000 Swiss francs (£12,400).

The four-year sanction runs from 30 October 2014, meaning Jeptoo will be 37 by the time she is eligible to return.