INDIANAPOLIS -- A new billboard that popped up over the past week on I-465 is an "attack on all Muslims," according to the Muslim Alliance of Indiana.

The billboard features the words "The Perfect Man" – apparently in reference to the founder of Islam, the Prophet Muhammad – followed by a list of attributes including "rapist" and "slave owner."

The billboard gives no indication who paid for it, save for the word "Truthophobes" – an Australian group dedicated to publishing anti-Islamic materials.

Rima Shahid, executive director of the Muslim Alliance of Indiana, says she was "heartsick" when she saw a photo of the billboard, especially since it has appeared just as the holy month of Ramadan has begun.

"At any point this would have been highly offensive, but we're in the holiest month of our faith, when we slow down and reconnect with our communities," Shahid said. "To have an attack on all Muslims during this period is very disheartening."

Shahid strongly condemned the billboard, saying it spread lies and misinformation about Islam and its prophet.

"It perpetuates hate. It perpetuates misconceptions about Islam, and it makes our neighbors think we believe things that just aren't true," she said.

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And not putting a name on the billboard? Cowardice, Shahid said.

"It's cowardly. It's cowardly," she said. "If this is something they believe in, stand by it. Endorse it. Let me call you and have a conversation. Why are they so afraid? I know why: It's because it's untrue."

"I feel bad for them," she continued. "First of all, they've been misinformed. Second, you must be in a lot of pain to go out and spread this hatred. That's a lot of burden to carry in your heart."

The Muslim Alliance of Indiana has reached out to Mayor Joe Hogsett and Congressman Andre Carson (D-Indianapolis), one of two Muslims in Congress, about ways to challenge the billboard.

In the meantime, Shahid says she takes strength from a story about the Prophet Muhammad.

"He would take a route every day, and every day this woman would throw garbage at him – this is not new to us. If it was me, I would probably pick it up and throw it right back at her, or take a different route," Shahid said. "But he continued. One day, this woman didn't throw garbage. He asked the neighbors, he said, 'Where is this woman?" He found out that she was ill, and that's why she missed a day. He went and visited her and told her, 'I hope you get well soon.' That's what Islam is."

"So this is no different," Shahid added. "This billboard is garbage."

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