Vidya Nair’s two young children were on a bike ride in their Ashburn neighborhood with their grandparents when they first noticed the words scrawled in black marker on a public trail sign.

“No Hindus,” the message said, in lopsided letters.

Since July, five similar incidents of vandalism in Ashburn’s Brambleton community have been reported to authorities and the Brambleton homeowner’s association. The Loudoun County Sheriff’s Office is investigating the cases, and the homeowner’s association announced a $500 reward this week to help identify those responsible for the graffiti.

Nair, who is Hindu, said she was surprised and saddened to see such a disparaging message in her community.

“I’ve been in this country for 14 years, and never once have I seen something like this or been exposed to something like this,” Nair said. “Loudoun . . . is so diverse. You don’t expect to see it here.”

Most of the reported cases involved similar messages — “No Hindus allowed” or “No Hindus, by order of Mosby’s Rangers” — written in black sharpie on neighborhood trail signs in the Brambleton community, authorities said. In the most recent case, a concrete barrier was spray-painted near Forest Manor Drive earlier this month, according to the sheriff’s office.

Liz Mills, spokeswoman for the sheriff’s office, said the cases remain under investigation. Authorities were not certain of the meaning behind the “Mosby’s Rangers” reference in this context, she noted. The name generally refers to a rebel Confederate battalion led by Col. John S. Mosby during the Civil War.

Nair, 36, said her primary concern was the impact of the vandalism on children in the community.

“I don’t want them to experience something like this,” she said. “My kids are pretty young — 8 and 10 — and they found it odd that somebody would say that. I told them that most likely, whoever wrote it they don’t really know what Hinduism is about.”

But the community’s response was immediate and supportive, Nair added. When she posted photos of the defaced signs on her Facebook page, comments poured in from people who shared her concern.

“Everyone kept saying this shouldn’t have happened,” she said. “Some people volunteered to go scrub it off.”

Richard Stone, the general manager of the Brambleton Community Association, said the association first thought the vandalism was the work of a trouble-making teen. But when the cases continued to be reported, the community heightened its response.

“We thought it was just an isolated incident back in July — a kid having fun or something,” he said. “But then it continued, and that’s when we stepped up our actions as far as the reward. . . . This is not something that we are going to tolerate.”

After the first occurrence of vandalism in July, four more reports followed in August and September, authorities said.

With the community on a heightened alert, Stone said, the incidents were being quickly reported and the graffiti swiftly removed.

Nair said she was heartened to see her neighbors take the vandalism so seriously.

“The response from everyone has been so supportive, and that’s really great to see,” she said.

Anyone with any information about the vandalism is asked to contact Deputy First Class R. Ortutay at 571-246-4156 or via e-mail at roy.ortutay@loudoun.gov. Callers wishing to remain anonymous are asked to call Loudoun Crime Solvers at 703-777-1919.