May 29 — A Chicago Fire Department diver died and two other divers were injured during a rescue attempt on the South Branch of the Chicago River Monday evening, officials said.

Juan J. Bucio, 46, was pronounced dead at Stroger Hospital at 10:02 p.m. He became separated from his partner while trying to rescue a man from the Chicago River near where it crosses Ashland Avenue on Monday night.

Two other divers were taken to Northwestern Memorial Hospital in good condition, according to the Fire Department. They were treated and released.

The fire department received a call around 7:50 p.m. after boaters saw a person jump into the water near Canalport Riverwalk Park in an industrial area near the Bridgeport neighborhood on the South Side, according to Chicago Fire Commissioner José A. Santiago.

It’s not clear what time divers entered the water. Around 8:25 p.m., Bucio became separated from his partner. “His partner turned around and he was missing,” Santiago said. “It was that quick.”

A mayday call immediately went out.

“We have a diver down, start making phone calls, let’s get people in, 10-4?” a Marine Unit supervisor said over his radio.

“You sounded muffled,” an officer answered. “I can’t copy.”

“We have a possible diver down. Start calling people. Let’s get some people in.”

Crews could be seen pulling a person from a boat onto a gurney as an ambulance waited on the shore nearby around 8:50 p.m. “We got the diver out, he’s going to Stroger, critical,” a battalion chief said into his radio.

The search continued Tuesday morning for the man initially reported missing in the river. Friends identified him as Alberto Lopez, 28.

Police and fire officials said the incident remained under investigation.

“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.”

About a dozen police and fire vehicles were stationed at Stroger late Monday, and officials blocked off Ogden Avenue in front of the hospital for at least an hour.

A group of firefighters stood outside the emergency room while Chicago police officers lined the entrance to the parking lot. Firefighters and police officers also gathered outside the Cook County medical examiner’s office.

Two firetrucks faced each other on Leavitt Avenue and stretched their ladders up and over Harrison Street. Firefighters from each rig used locking rings to secure and hang a flag over Harrison Street, as is customary for line of duty deaths.

Firetrucks and engines lined Harrison Street on the way to the morgue. Just after 1 a.m., two police SUVs led a procession from the hospital with Ambulance 65 carrying Bucio’s body.

As the ambulance and trailing SUVs turned left into the medical examiner’s office, the cars following in procession turned right.

Firefighters from Truck 7 folded the flag behind their rig just before 1:30 a.m. as fire crews and police officers that had lined the route returned to their firehouses and patrol districts.

Bucio is the 13th Chicago firefighter to die in the line of duty since 2000, according to data from the Illinois Fire Service Institute, and the first line of duty death since Daniel Capuano fell through an open elevator shaft at a vacant warehouse in December of 2015.

He joined the department in 2003, and became of a member of the dive team in 2007. He lived in the Clearing neighborhood, in the 6300 block of West 63rd Street on the Southwest Side.

Bucio is survived by nine siblings, including a sister who is a member of the Chicago Police Department and a brother who is a member of the Chicago Fire Department. He has two sons, 9 and 7.

___ (c)2018 the Chicago Tribune Visit the Chicago Tribune at www.chicagotribune.com Distributed by Tribune Content Agency, LLC.