Yes. But probably not with intentions of hurting your grandmother unless they were probably worried of getting caught in some cross fire. But there was a ruthless gang called the black hands in 1915. In fact there was a news article from the "Daily News" at that time that came out on May 25th 1915 which said that in the first 93 days of that year 55 bombs had been exploded in the Italian district. It was said that not one of them had been set off for any other reason other than the extraction of blackmail. It is rumored that the black hands were immigrant Sicilians but no evidence was ever obtained to connect them. Chicago at that time definitely had its share of gangsters, criminals, madams, and crooked politicians. Around this time the Chicago Italian Mob Boss was Big Jim Colosimo who was succeeded by his New York born bodygaurd and underboss Al Capone. Capone eventually took out (killed) his boss Big Jim to take advantage of the lucritve bootlegging, gambling, and prostitution business. That's just a little history to go along with it, but your grandmother probably feared the mysterious and ruthless blackhand gang at that very point in time.
AnswerYES
Gangsters of the Hills - 1915 was released on: USA: 3 September 1915
In the 1920's
St. Valentine's Day Massacre
Both were Prohibition era Chicago gangsters.
Chicago Whales ended in 1915.
Chicago Military Academy was created in 1915.
Cathedral Shelter of Chicago was created in 1915.
Chicago Opera Association was created in 1915.
Columbus Park - Chicago - was created in 1915.
The Thompson sub-machine gun invented in 1919 was called the Chicago typewriter, not the Chicago piano. That name was given by the US Navy to the ship mounted 20 mm antiaircraft gun which was usually mounted in a Quad assembly for air defense. The weight of this weapon would have made it quite impractical for use by Gangsters.
Chicago Municipal Tuberculosis Sanitarium was created in 1915.
The collective nouns are a knuckle of gangsters and a mob of gangsters.