The widow of British comedian Rik Mayall said that her husband suffered a heart attack after a morning jog, which may have lead to his sudden death on Monday. Mayall was just 56-years-old and had not stopped working on British television and in films.

His wife, Barbara Robbin, has told the U.K. media that Mayall suffered “an acute cardiac event” after his morning run, reports The Telegraph.

This is her latest theory for a cause of death for her husband. As previously reported, on Monday, she suspected that Mayall had an epileptic fit. She also told reporters on Monday, “We don't know yet what happened. He had a strong heart, so I don't think it was a heart attack. But we just don't know until the coroner's report.”

Unfortunately, that coroner's report is in and it did not provide any answers. The BBC reports that the initial post-mortem examination was inconclusive, the West London Coroner’s Office said Thursday.

Mayall, who is best known for his roles on The Young Ones and Bottom, died Monday, his management confirmed. He had previously survived a near-death experience in 1998, when he was involved in a bike accident. After that, he went right back to work and continued acting up until his death.