A fire department diver died after he jumped into the Chicago River in search of a boater who had fallen overboard, officials said.

According to the Chicago Fire Department, Juan J. Bucio, 46, was with a team of divers called to the river in response to a report that a boater had fallen overboard at about 8 p.m. Monday.

Bucio jumped in the water but became separated from his dive partner.

“Immediate search started with the backup divers,” said Fire Commissioner Jose Santiago.

Bucio was found, pulled from the water and rushed to Stroger Hospital, where he was pronounced dead shortly after 10 p.m.

Bucio “tragically passed away answering a call of a person in the water,’ the department said on Twitter. Two other divers suffered non-life threatening injuries.

The department was trying to determine what exactly happened, said spokesman Larry Langford said Tuesday. The results of an autopsy were expected to be released Monday afternoon but Langford said unconfirmed reports that perhaps Bucio was struck by a boat appeared to be false.

“Chicago police detectives are investigating the circumstances of his death, but at this time there are no signs of any foul play or criminality,” police spokesman Anthony Guglielmi said in an email. “Based on all available evidence thus far, this appears to be a heartbreaking tragedy.”

As of early Tuesday afternoon, the man who fell overboard had not been found.

Bucio, joined the Chicago Fire Department in 2003 and became a member of its dive team in 2007. He had two children, sons ages 7 and 9. He also had nine siblings, including a brother at the fire department and a sister at the police department, Santiago said.

“Please,” Santiago said, “keep this family in your prayers.”

(AP)