A man was killed in Longmont on Tuesday after he was buried in a trench while doing repair work for Denver-based Castillo Excavation, the Longmont Fire Department said.

On Thursday, the Boulder County Coroner’s Office identified the man as 87-year-old Robert Castillo of Denver. Castillo is the owner and manager of Castillo Excavation, according to the Better Business Bureau.

An autopsy has been completed, but results regarding his cause and manner of death are pending further investigation, the coroner’s office said.

The fatal trench collapse happened Tuesday at noon when Castillo and his company were replacing a sewer line at a house at 152 Baylor Drive, the fire department said. Castillo was buried when the trench collapsed.

It took approximately two hours for rescuers to get Castillo out of the trench, at which point he had already died.

The cause of the trench collapse is under investigation. Officials with the fire department said the 9-foot-deep hole was not shored up, meaning walls and braces were not used to secure the trench.

Foul play is not suspected at this time.