LAUSANNE, Switzerland -- Former Chicago and Boston Marathon winner Rita Jeptoo has had her doping ban doubled to four years by the Court of Arbitration for Sport.

In a ruling published Wednesday, the CAS judging panel stripped Jeptoo of her 2014 win in Boston, plus results, prize and appearance money dating back to April 17, 2014. The Kenyan runner previously lost her 2014 Chicago victory.

Jeptoo had been due to earn a $500,000 bonus for leading the World Marathon Majors series standings for the combined 2013 and 2014 seasons. She won back-to-back Boston and Chicago titles in 2013.

Now 35, Jeptoo tested positive for EPO in a September 2014 sample given during training for the Chicago race.

CAS said it upheld the IAAF's appeal to increase Jeptoo's original two-year ban, which was imposed by Athletics Kenya and was to expire this week. Athletes can be banned for four years over a first offence if there are "aggravating circumstances."

"(It) was obvious to the panel that the athlete used EPO as part of a scheme or plan," the panel ruled, citing evidence including her long relationship with the unidentified doctor and "multiple visits to see him" which she hid from her manager and coach.

The "undisputed source" of the red blood cell-boosting hormone was an injection by her doctor, the ruling stated.

Jeptoo was also criticized for "deceptive and obstructive conduct throughout the (CAS) proceedings."

"The athlete provided various differing accounts of the circumstances leading up to the injection and also regarding her relationship with that doctor," the court said in a statement.

A scheduled two-day court hearing in April was postponed and two different lawyers withdrew from representing her. When a hearing in Switzerland was held in July, Jeptoo initially joined by telephone but "opted to leave the hearing during the opening statements," the court said.

The Kenyan track body also pulled out of taking part.