2:08 PM PT -- Moi Teaching and Referral Hospital tells TMZ Sports that Dickson Ndiema's cause of death was due to "inhalation burns and sepsis with resultant pulmonary edema."

Pulmonary edema happens when too much fluid is in the lungs which makes it difficult for someone to breathe.

The ex-boyfriend of Ugandan Olympian Rebecca Cheptegei has died from the injuries he sustained after allegedly killing the runner in a fiery attack, according to local reports.

Dickson Ndiema succumbed to the ailments at a local hospital, authorities said. At the time, it was reported he suffered severe burns in the domestic violence incident that claimed Cheptegei's life.

"At the ICU he developed respiratory failure as a result of the severe airway burns and sepsis that led to his eventual death on Monday at 6:30 PM despite life-saving measures," Kenya's Moi Teaching and Referral Hospital CEO Dr. Philip Kirwa said.

As we previously reported, Ndiema attacked the Olympic distance runner after an alleged argument over property on September 1 ... where he set her ablaze outside her home.

Cheptegei suffered burns that covered 80% of her body ... and tragically, she died days later due to multiple organ failures.

She was buried this weekend in the Kapkoros, Bukwo District in Uganda.

The 33-year-old just competed in the 2024 Olympics in Paris ... and represented Uganda in several other contests -- including the IAAF World Cross Country Championships and World Athletics Championships.

Cheptegei also won the Padova Marathon in Italy in 2022 and set an Uganda record of 2:22:47 in the marathon.

The Uganda Athletics Federation addressed the loss at the time ... saying, "We are deeply saddened to announce the passing of our athlete, Rebecca Cheptegei, early this morning, who tragically fell victim to domestic violence."