Federal authorities are lending a hand as suburban Chicago police keep hunting for a gunman who shot five women to death at a Lane Bryant clothing store over the weekend.

An FBI spokesman in Chicago, Ross Rice, said Tinley Park police have asked for the agency's assistance. But he won't say just how the FBI is helping out.

Tinley Park police Sgt. T.J. Grady on Monday gave an updated description of the killer. Grady said he is a black man with a clean-shaven, medium complexion, 5 feet 8 to 5 feet 10 inches tall, weighing 230 to 260 pounds. He was about 25 to 35 years old, with broad shoulders.

The killer wore black jeans with writing and embroidering on them and some sort of rhinestone decorations on the rear pocket, Grady said. He had on a black, waist-length jacket with no writing and a charcoal knit cap concealing thick, braided hair. He had a receding hairline and let one braid fall to his cheek. That braid had four light-green beads at the end.

One Victim Survives

Tinley Park police also said Monday that a sixth victim survived the shooting and is aiding in their search for the gunman. Police had concealed the information the day of the shooting.

Tinley Park Mayor Ed Zabrocki told NBC5's Kim Vatis Monday that police didn't want the suspect to know he had left a witness behind.

Five women were killed Saturday morning when a man allegedly entered a Lane Bryant clothing store in Tinley Park and shot them.

The Will County Coroner's Office said all five died from gunshot wounds.

The survivor was grazed in the shooting and called 911, Vatis said. The mayor said the woman is assisting in the investigation with hopes of a composite sketch being released soon.

The mayor also said that he is beefing up patrols in Tinley Park, including protection at the homes of the victims' families.

She was taken to St. James Hospital and Medical Centers in Olympia Fields.

"We did receive one female victim from the Tinley Park shooting. This person was received yesterday," said hospital spokeswoman Sherry Sissac. She would not release any more details, but sources said the woman was released from St. James early Sunday.

On Saturday, authorities said no one had survived the attack. When pressed about a possible survivor during a news conference Sunday, Tinley Park Police Chief Mike O'Connell refused to comment.

Victims Identified

Officials said the victims -- a store manager and four shoppers whose ages ranged from 22 to 37-- were herded to the back room of a clothing store during a botched robbery attempt, tied up and shot.

In addition to the unidentified survivor, the five fatalities were identified as Carrie Hudek Chiuso, 33; Connie R. Woolfolk, 37, of Flossmoor; Sarah T. Szafranski, 22, of Oak Forest; Rhoda McFarland, 42, of Joliet; and Jennifer L. Bishop, 34, of South Bend, Ind.

The brother of one of the victims told NBC5 that his sister had been shot in the head and, he feared, beaten. He said she was bruised and her hands were tied behind her back.

Police would not confirm that information, but NBC5's Phil Rogers reports that the victims were bound and shot execution-style in the head.

The robbery unfolded in the full-figured women's retail store, near 191st Street and Harlem Avenue just south of Interstate 80. At 10:44 a.m., police received a call reporting gunshots inside the store. O'Connell said police arrived at the scene within minutes.

Inside, they found mayhem.

"There is no question it was a horrific scene,'' a police source said. The women's bodies were found in a back room.

Grady said police were "pretty sure'' the shooter acted alone.

Why the shooter targeted the small store in the strip mall is anyone's guess.

"It's not a place where you would find a lot of cash,'' a police source said, adding that the man did make off with some valuables.

Also unknown is how and why the robbery turned deadly.

The store did not have its own security camera, O'Connell said, but authorities are checking for cameras within a few miles of the sprawling center.

Built in 2005, Brookside Marketplace includes some storefronts that have not opened yet, making the Lane Bryant store more isolated, the police source said.

"We're checking every possible means of getting out of this area," Grady said.

There are at least 40 investigators working on the case. Police searched neighboring stores and cars in the parking lot and used a police helicopter to search the surrounding area, Grady said.

Police even locked down stores in the center, including a SuperTarget, PetSmart and Office Max, searching each with guns drawn.

"We are very comfortable that the offender is out of the area,'' O'Connell said.

Shopper Charlotte Vaitkus, an area resident, said she wanted "to issue a statement to the mayor because of the frequency of crime off Interstate 80. We just don't feel safe."

Victim's Husband Recognizes Wife's Car

Hudek Chiuso's husband was waiting for her to return home from a quick shopping trip to a nearby Lane Bryant clothing store Saturday when he saw the news report: There had been a multiple shooting at the store.

Even worse, he recognized her car parked in front of the store.

Soon after, her family learned the news: She was one of five women gunned down in a robbery turned deadly at the Brookside Marketplace shopping center in Tinley Park.

The Frankfort woman's family "is brokenhearted,'' said Hudek Chiuso's sister-in-law, Jennifer Hudek.

"That son of a bitch took more than just her,'' she said of the gunman. "He took a piece of each of us.''

After Tony Chiuso saw his wife's car in news reports, he left their Frankfort home for the Tinley Park police station. There, he eventually learned the news.

"He's not doing too good,'' said his father, Tony Chiuso.

Mayor, Governor Respond To Shootings

Zabrocki said that after the shooting, Tinley Park sent extra police patrols into the residential neighborhoods nearby.

"We're very sad about it," a clearly shaken Zabrocki said from the scene. "We're a victim of our society that we live in."

Gov. Rod Blagojevich's office released a statement Saturday in which the governor pledged the state "stands ready to assist Tinley Park law enforcement in any way they need." The governor also stated, "There is no imaginable justification for the deadly and random violence that stole those innocent lives in Tinley Park today. My thoughts and prayers go out to the families of the victims and the many people who witnessed the tragedy."

Police are offering a $1,000 reward for any information leading to the arrest of the gunman.

Lane Bryant's parent company, Bensalem, Pa.-based Charming Shoppes Inc., said it was offering a $50,000 reward for information that could lead investigators to the gunman.