John-Michael Tebelak; Author

John-Michael Tebelak, a playwright who wrote the book for the rock-gospel Broadway hit, “Godspell,” was found dead Tuesday in the bathtub of his apartment. He was 36.

Tebelak’s death was believed to be due to natural causes, pending the medical examiner’s findings, said Sgt. Ed LeSchack, a police spokesman. The writer’s mother, Genevieve Tebelak, said her son had an enlarged heart and died of a heart attack.

Tebelak wrote the script for “Godspell” 14 years ago as a master’s thesis at Carnegie-Mellon University in Pittsburgh. With music by Stephen Schwartz, it opened at the Cafe LaMama in 1971, before transferring to Off-Broadway and then Broadway.

The play also was made into a movie, and has become a staple of traveling companies. It is based on the Gospel according to St. Matthew.

“John got the idea for Godspell at an Easter service that was not too inspiring,” his mother said. “It’s ironic that the Easter season is also the time of his death.”

Tebelak later became dramatist-in-residence at the Cathedral of St. John the Divine in New York City, staging several plays there, including a one-act play about the Americans held hostage in Iran.