(CNN) A civil rights marker about Emmett Till on the Mississippi Freedom Trail has been vandalized twice in the past two months, according to the firm that manages the trail.

The historical marker outside the grocery store where 14-year-old Till was accused of whistling at a white woman while visiting his family has to be refurbished due to the damage by vandals, said Allan Hammons, whose company manages the Mississippi Freedom Trail.

He said that in May someone scratched the marker, and over the weekend, it was noticed that someone had peeled off the back of the marker, where it contained photos and writings about Till.

"This site is a significant moment in the civil rights movement," Hammons said. "People were outraged and shocked at this incredible criminal act. What Mississippi chose to do by creating the freedom trail was committing themselves to telling the unvarnished truth."

Scratches mar a historical marker outside the grocery store where Emmett Till is said to have whistled at a white woman.

Till was kidnapped and lynched in Money, Mississippi, in 1955 after the incident at the Bryant Grocery store. Two white men were arrested in the case, but were acquitted by an all-white jury in Mississippi that same year.

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