The BBC reports that Dickson Ndiema, who was Cheptegei's boyfriend, died from burns he sustained during his attack on the Ugandan athlete after some of the fuel he poured on her splashed on him.
Cheptegei recently competed at the 2024 Olympic Games in Paris and was one of Africa’s finest female long-distance athletes.
The marathon runner was admitted to the hospital after she suffered severe burns from being doused in petrol and set on fire and died last Thursday.
Authorities said the incident happened in Kenya, where she had been living and training, and was targeted after returning from church.
Rebecca Cheptegei's boyfriend also dies from burns
According to the BBC, Cheptegei and her partner were involved in a quarrel over a piece of land before he set her ablaze.
However, the severity of the attack saw Ndiema also sustaining burns on “40% of his body,” the hospital said.
While Ndiema had been on admission at the hospital in the last one week, he was confirmed dead on Monday.
A statement from the Moi Teaching and Referral Hospital said despite life-saving measures, he died after developing respiratory failure.
"He developed respiratory failure as a result of the severe airway burns and sepsis that led to his eventual death on Monday evening at 18:30 hours [15:30 GMT] despite life-saving measures," the statement said.
For some people on social media though, Ndiema’s death is the consequence of his cruel act, while others have condemned him to hell.
Meanwhile, Cheptegei’s death adds to the alarming rate of domestic violence against female athletes in Kenya.