Trump is a pathological liar and he's almost incapable of recognizing, let alone telling the truth. He's lied about the size of the crowd at his inauguration, lied about voter fraud, lied about climate change, lied about making Mexico pay for the wall, about being an environmentalist. There are countless lies, and he thinks that if he perpetuates them, they'll become truth. Disturbing. Sad.
Trump lying? Its sad that a president lies so much that you just have to ignore it after a while. People need to stop this conspiracy theory that Trump's lies are part of some grandiose plan. They're not. They're how Trump has acted for his entire life. He keeps doing it because it's all he knows. The man does not know how to be honest and at 70 years old he's not going to suddenly change how he acts. Lying and self-aggrandizing are as much a part of Trump as his tiny hands are. This is how he's always acted.
It was much more likely that he was provided with incorrect information from someone in his team. Donald Trump is in fact frequently consistent with his statements which are not lies most of the time. The other possibility other than wrong information provided was that he might of been counting on it as there are shootings every day in Chicago, but I seem this possibility to be much more unlikely. Whatever it was. He is definitely not a pathological liar (unlike Hillary).
I don't think he prepares enough for it to be an intentional lie. He just speaks off the top of his head without bothering to refer to notes for accuracy. Trump needs to give a nod to getting the facts straight if he wants to show his credibility is worth anything.
There are plenty of stories which corroborate findings of the issues surrounding Chicago and its problematic areas. It could have been that Trump received wrong information. However, there is no question that the city has and still is experiencing turmoil. That is a statement Trump has not said to mislead.