Before the bloodshed one year ago, the storefront across the street from the Suitland Federal Center was tidy and thriving. Owner Mary Frances McDonald had regular customers, people she knew by name, her daughter said.

Today, the Suitland Florist is shuttered. An aluminum roll-down gate, flush with the littered sidewalk, guards what few items remain inside. The small strip mall has deteriorated over the past year, authorities said, as other nearby businesses have closed. Many of the apartments behind the stores are boarded up or vacant.

Last week, McDonald's daughter knelt outside the florist shop and lighted two candles, one for her 76-year-old mother and the other for Madeline "Mattie" Thompson, her mom's longtime friend. Both were stabbed to death inside the shop Sept. 24, 2003, a midmorning, brazen attack that left the community shaken and many shopkeepers in fear.

A handwritten note from McDonald's daughter, taped to the shop gate, read: "As you pass by and the light is out, light the candles for the spirits of Mary McDonald and Madeline Thompson."

On Friday, the one-year anniversary of the slayings, investigators returned to the scene to hand out fliers with details about the homicides. False leads had trickled in for a while, but the case has since stalled. The detectives went door-to-door in the area, afterward saying they remain upbeat about solving the slayings of the two church-going grandmothers.

Authorities said one of the most promising clues is a T-shirt that was discarded by the attacker or attackers. It is black with blue squiggling letters that read "CLASS OF 2003." A blue roadrunner, its tongue sticking out, is being chased by a white cloud that looks like a misshapen tortoise that reads "WHO RUN IT." Only 70 shirts like it were made, investigators said, but tracing it to its owner has been difficult because it could have been given away or sold.

"We're hoping that with it being the one-year anniversary, someone will come forward with new information," said Robert Nealon II, a commander of the Prince George's County Police Department's homicide division. "A lot of times, something sits heavy on someone's mind . . . and so we're hopeful someone will come forward with whatever information they have."

McDonald and Thompson, 73, were killed in what police believe was a robbery of McDonald's shop. Both were stabbed several times. A U.S. Postal Service employee found the bodies at 10:38 a.m.

McDonald's daughter, Ann Swann, 52, stood over the wavering flames Friday and spoke about the grief that has saturated the days since her mother's death.

"When I get home, I look across the hallway and she's not in her room. Some days I sit on her bed to breathe her scent and I just cry," she said in a soft voice, adding that the past several months have been particularly rough because all three of her sons are stationed in Iraq, making the anniversary especially lonely.

"There was just a tremendous impact on the community," she said. She remains baffled by the motive behind the slayings. "If [the suspects] needed money, they could have come in and swept the floors and she would have given them $20. She was like that.

"Now I just hope that if people out there want to embrace the families of these women, they will call in with information they have," said Swann, principal of Gladys Noon Spellman Elementary School in Cheverly. "Now is the time to let it go. Don't be afraid. The police will protect your identity. The suspects are still out there and they could do it again for no reason to someone else's family."

Police asked anyone with information about the homicides, or the source and owner of the T-shirt, to call the department's Crime Solvers at 301-735-1111. Callers can remain anonymous, and a cash reward of up to $1,000 is being offered for the tip that leads to the arrest and indictment of the person or people responsible.

Ann Swann, above, lights candles outside the shop where her mother and a friend were killed a year ago. At left, homicide detective Eric Chhay, left, talks to Bryan Gordon while handing out fliers seeking information in the case. McDONALDTHOMPSON