Police released enhanced photos of the two armed men who robbed and pistol-whipped Orange Line passengers heading into downtown Chicago Wednesday during rush hour.

The surveillance photos provide a clearer glimpse of the two men believed to have committed the crimes.

The robbery happened at 4:13 p.m. on the train as it traveled between the Halsted and Roosevelt stations, police News Affairs Officer Veejay Zala said.

Two armed suspects took various items from five riders and police are reviewing surveillance video in the case.

On Thursday, the Guardian Angels joined in the hunt.

“I'm in shock,” Fuentes said. “4 p.m. and they're not wearing any masks on a train coming into downtown as opposed to the far South side or the west side where some of the stations are very isolated."

The group, a volunteer-based community search patrol, was making rounds throughout the area between the Chicago Transit Authority's Halsted and Roosevelt stations early Thursday morning warning commuters about the incidents and asking for tips leading to the suspected robbers.

"The good thing is there's a lot of video and pictures out there,” said Miguel Fuentes, national director for the Guardian Angels. “The CTA is working with the police department so we're asking the public if you recognize these individuals call the police or if you don't feel comfortable speaking to police, call the Guardian Angels and we'll forward the information."

The group handed out flyers advising commuters to be alert while riding trains and waiting at platforms, take off headphones, put electronic devices away and report criminal activity immediately.

Passenger Romelia Garcia told NBC 5 that she was the only one of about 20 passengers in the train car to fight back. She suffered a bruise on her forehead where one of the men hit her with a gun and other assorted bruises but she refused to give up her purse.

Fuentes, however, is encouraging riders to give up their belongings.

"In a situation where someone produces a weapon, a knife or gun, give your valuables up,” he said. “You can replace those."

Fuentes said the Guardian Angels fear more attacks could take place if the suspects aren't caught.

“They definitely are bold to do this,” Fuentes said. “There's cameras on the train, cameras on the platform and so we need these guys off the street immediately. People don't commit crimes like this just one time and stop."

Anyone with information regarding the suspects is asked to call Area Central Detectives at 312-747-8380 or the Guardian Angels at 312-217-7245.