Story highlights "We have a much better understanding than Mr. Trump," she said

Trump: Drugs are a very, very big factor in what you're watching

Washington (CNN) Charlotte Mayor Jennifer Roberts said Republican nominee Donald Trump's assumption that drugs are a factor in her city's protests is "presumptuous."

"It's presumptuous for him to make conclusions like that without having thorough conversations with some of the folks who are here on the ground and are really aware of what's going on and what the reasoning is," she told CNN's Carol Costello on "Newsroom."

Trump tied the eruption of violent protests to narcotics, telling a Pittsburgh crowd Wednesday that "drugs are a very, very big factor in what you're watching on television at night."

The GOP nominee offered no evidence to back up that claim but Steven Cheung, a Trump campaign spokesman, later said it was "obvious" that Trump was "referring to the recent increase in drug related deaths and subsequent news reports, thus making it a hot button issue."

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