The boy was dressed up as Spider-Man in the backyard of his home on the 1000 block of East 84th Street when two men appeared in the alley and opened fire.
Police said the shooters are apparent gang members and one of them used a semi-automatic handgun. Authorities said the Shannon family has no gang affiliations.
"We believe that our suspects are gang members and mistaken this family as rival gang members, even though they're not," said LAPD Detective Christ Barling. "I'm assuming that these cowards were not trying to shoot a 5-year-old kid, and hopefully someone will come forward and turn these cowards in."
Anyone with information regarding the shooting is urged to call Crime Stoppers at (800) 222-TIPS or (800) 222-8477.
If you'd like to send well wishes:
The Shannon Family
P.O. Box 180203
Los Angeles, CA 90018