It ain't all roses, hearts and chocolates.
On February 14th, 1929, 7 men of the "Bugs" Moran Gang were brutally murdered by what is now believed to have been possibly Capone's gang dressed up as cops. Prior to the Massacre, Chicago had been a bit loose with their gangsters, treating them a bit like celebrities who provided jobs and booze in the era of the Volstead Act.
A bizarre but telling detail of the incident: One victim (with 14 bullets in him) was still alive when found. Asked by the cops who had done the deed, he said "Nobody shot me".
Wikipedia has a phenomenal amount of info on the gruesome crime.