Ugandan marathoner Rebecca Cheptegei, who competed in the Paris Olympics, has suffered burns over 75 percent of her body after her boyfriend allegedly doused her with petrol.

Cheptegei is in critical condition at the Moi Teaching and Referral Hospital in Eldoret, Uasin Gishu County, following the attack on Sunday afternoon, according to the police.

Trans Nzoia County police commander Jeremiah Ole Kosiom said that Cheptegei's boyfriend, identified as Daniel Ndiema Marangach, was also burnt in the attack, which was described as a domestic dispute.

According to a report filed by Kinyoro District Chief, Madam Rose Chebet, the Sunday incident occurred at around 2pm when Marangach secretly entered her compound while her children were in church.

Armed with petrol, he allegedly poured the flammable liquid on Cheptegei and set fire to her. The resulting fire quickly engulfed her and, in a disturbing twist, Marangach also caught fire when he lit a matchstick. 

At the scene, police discovered a five-litre yellow jerrycan, a bag and a black marvin, believed to belong to Marangach. 

A burnt mobile phone, believed to be Cheptegei's, was also found.

Cheptegei,33, who finished in the top 50 in Paris, has a house in Kenya where she stays when she trains in the country.

She took part in the 2021 World Mountain and Trail Running Championships in Chiang Mai, Thailand held in 2022, winning gold in the Up and downhill race.

Police have since launched investigations.