CHICAGO _ The two Chicago officers scrambled up the embankment and walked south on the Metra tracks, keeping an eye on an approaching train as they searched for a shooting suspect.
The noise apparently masked another train coming up fast behind them.
There's no indication the officers saw the South Shore train before it struck and killed them on a viaduct over 103rd Street on Monday evening, according to video taken by a body camera on one of the officers.
"They had no idea the train was behind them," police spokesman Anthony Guglielmi said.
Based largely on the bodycam footage, Guglielmi released new details Tuesday about the deaths of Officers Eduardo Marmolejo, 36, and Conrad Gary, 31, both fairly new to the department and fathers of young children. They are the third and fourth Chicago police officers to die in the line of duty this year.
The officers had been called to an area near 103rd Street and Dauphin Avenue around 6:20 p.m. after a ShotSpotter sensor picked up the sound of gunfire, police officials said.
Marmolejo and Gary spotted a suspect, got out of their car and climbed up the embankment to the tracks, Guglielmi said. The footage shows the officers crossing the viaduct, heading south where they thought the suspect went.
"They were deciphering the offender's direction of flight," he said. Moments later, a Metra Electric train approached them. They stayed on the southbound side of the tracks "but unfortunately they're not aware there's a southbound train.
"They hear the noise (of the northbound train), we suspect. That masks the noise of the other train that is right behind them," Guglilemi said. The train struck the officers near the 103rd Street Rosemoor stop.
Shell casings were found on the scene, near where the ShotSpotter had picked up gunfire, but there are no reports that the officers were shot at or fired their guns.
Police recovered a weapon near where the officers were struck and were questioning a person of interest Tuesday, Guglielmi said.
After the bodies were taken to the morgue, in a procession of police cars, police Superintendent Eddie Johnson and other staff viewed the video showing the sequence of events, Guglielmi said. Police continued to search the viaduct Tuesday morning to make sure that they had not missed any evidence. Trains were not stopping at the station.
Marmolejo and Gary are among four Chicago police officers killed while on duty this year.
On Nov. 19, Officer Samuel Jimenez, 28, was killed in a mass shooting at Mercy Hospital & Medical Center on the Near South Side. Two women, Dr. Tamara O'Neal, 38, and pharmacist Dayna Less, 24, were also killed before the gunman shot himself.
On Feb. 13, Cmdr. Paul Bauer, 53, was fatally shot while chasing a suspect to a stairwell outside the Thompson Center in the Loop.
Marmolejo and Gary were assigned to the Calumet District on the Far South Side where three other officers have died this year. Two died from suicides outside the district's police station on East 111th Street. The third officer, 47-year-old Vinita Williams, died in July after collapsing at the station.
