That said, there was a limited study done in Malaysia that seemed to indicate a decrease in crime in one area where murals appeared.  https://www.researchgate.net/publication/309891802_The_Effect_of_Mural_on_Personal_Crime_and_Fear_of_Crime

Here in Indianapolis there is a long-term, anthropological study going on to measure the impacts of a number of arts initiatives on the city, but it doesn't call out murals specifically.  Anecdotally, we at the Arts Council have found that new murals eliminate gang tagging if they are placed on walls that previously were magnets for it, but only for a while and only if the mural is meticulously maintained. As soon as people start to take the mural for granted, the tagging reappears. We have also seen a correlation between "cool" murals and increased economic activity, but it's hard to say whether it's causal or not, or which direction it runs, and it's a whole other issue who the economic activity includes and excludes. There is no study saying all this, just observation.

I have attached some literature that could be of use to you. I have tons more--feel free to contact me.