Updated 02/18/11 – 4:22 p.m.

CHICAGO (CBS) — Chicago police were out in force in the Hegewisch neighborhood on Friday, searching for the men who robbed a dollar store and then fired at police during a standoff Thursday night.

Police were called to the Family Dollar store in the 13300 block of South Brainard Avenue around 8:30 p.m. Thursday after receiving reports of two men loitering in the parking lot.

As CBS 2’s Suzanne Le Mignot reports, when officers entered the building, at least one of two robbers fired shots at police and officers returned fire, while customers and workers got on the floor for safety.

The robbers got away through a back door. A third suspect was driving a get away vehicle.

Police found a pool of blood in the alley behind the dollar store and several drops of blood were also found throughout the neighborhood.

Sources said the blood is from one of the suspects who was wounded when the robbers exchanged gunfire with police.

Chicago police and Cook County Sheriff’s officers used bloodhounds as they searched nearby alleys and streets in an effort to find the robbers on Friday. The dogs were following the scent left behind by the drops of blood.

U.S. Marshall’s deputies, clad in riot gear and armed with machine guns, also assisted in the search.

One local resident, who asked to remain anonymous, said his friend called police after discovering drops of blood in her gangway and blood in this alley.

“She knew it could have been something to do with last night. She heard about the shooting and all the helicopters and stuff,” he said.

According to a police report, a gang member was bragging on Facebook that there was going to be a robbery and shooting at the dollar store Thursday night and a shooting at nearby Mann Park, stating “We gonna put Hegewisch on the map tonight.”

Sources said Thursday’s robbery was at least the tenth time in a year that the Hegewisch Family Dollar store was the target of a robbery.

“It’s kind of predictable that something like this would happen because I’ve been in there where the girl was all the way in the back room and there’s no one else in there. There’s one person working there,” the witness said.

Sources said that police are reviewing video from nearby police surveillance cameras. Sources also said cameras inside the store might have been instrumental in capturing information and descriptions of the suspects.

The Sun-Times Media Wire contributed to this report.

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