An 11-year-old girl at a sleepover party was among the four people killed in the 40 or so shootings in Chicago this weekend. From the AP report:

A police spokeswoman, Janel Sedevic, said Sunday afternoon that nobody has been arrested in Friday's shooting. He declined to say if there were any suspects. Investigators believe the person who fired the fatal shot was apparently aiming at a rival in a gang dispute, but missed. The bullet went through an open window of the house, pierced a wall and struck Shamiya in the back of the head."

An NBC data map showed the geographical range of the incidents within the city:

The weekend continues what has already been a pretty terrible month for Chicago. From Reuters:

City officials condemned as unacceptable a spree of gunfire over the Fourth of July holiday weekend that left 17 dead, with 53 people shot, including five by police. Authorities said at the time that shooting deaths in Chicago were down for the year."

More than 40 people were also shot in Chicago over Easter weekend, prompting the creation of a federal prosecutorial unit.

As a city, Chicago has the nation's  most stringent handgun laws. There are no gun shops, no gun ranges, and handguns were banned until a 2010 Supreme Court decision made the ban unenforceable.

Chicago's violence has made the city a focal point for debate between gun rights' activists, who believe the gun laws don't make the city safer, and advocates of gun control, who argue that without uniform gun laws, any efforts made by the city to stem the flow of illegal weapons is meaningless.