[Lazamataz]

It is not sloppy English. Since they shootings happened in various locations ACROSS THE CITY, it is logical to say ACROSS CHICAGO.

It's awkward, at best.

Tax-chick, your professional opinion?

[UCANSEE2]

If one reads the article, the shootings happened to the NORTH, SOUTH, EAST, and WEST. ACROSS means from one side to the other , of an item or area, such as a city.

These shootings happened, LITERALLY, ACROSS the CITY of Chicago.

Awkward sounding it may be, but proper English it is.