Four people shot dead 'execution-style as they slept in their seats' on Chicago area train
Four people have been shot dead "execution style" on an early morning commuter train near Chicago.
Police said they were seated apart in two carriages and appeared to have been attacked while asleep in their seats as the train was moving.
The attack, which took place before 5.30am local time, was described as an "execution-style" killing.
Officers were called to Monday's incident and pronounced three of the victims dead at Forest Park station and a fourth person later died in hospital.
The victims were three men and one woman, according to the Cook County medical examiner's office.
The suspect escaped but was later arrested with a gun on another train, said Forest Park Police.
They said the attack appeared to be an isolated incident with no further threat to the community.
Authorities later charged Rhanni S Davis, 30, with murder on Tuesday.
Information on the victims' identities is yet to be released.
Forest Park is a suburb about 10 miles west of downtown Chicago and has a population of about 14,000.
"It's a horrible tragedy that four people are dead on Labor Day weekend," said local mayor Rory Hoskins.
"Our police department and our fire department respond to this location probably more than any other location in our jurisdiction."
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A regular traveller on the route, Sean McNulty, said criminal activity is not unusual on trains in that area.
"You just kind of get used to it," he told the Chicago Tribune. "I keep my eyes open because I want to know what's going on around me at all times."
The Chicago Transit Authority called the killings a "heinous and egregious act of violence".
Mr Hoskins added his teenage son takes the train where the suspect was arrested to school and he watched a little closer than usual at Tuesday morning's drop-off.
"People are rattled," he said. "We want to make them feel safe."
