The victims' bodies were found in the 5800 block of 13th Place, Gary police said.
The deceased have been identified by the Lake County Coroner as Antonio Dove, 27; Briean Jiles, 22; and Michael Andrews, 34.
Witness Gloria Andrews, who identified herself as the mother of the one of the deceased, said she heard about 15 gunshots, then the sounds of women screaming and crying. She then saw police cars and the bodies outside of a home.
"I called 911 and they did come. I came out the back door and noticed a lot of gunshots and then three bodies on the ground. One was my son," Andrews said.
By Sunday morning, the scene had been cleared, but a small memorial could be seen in front of a home.
Witnesses and family members said the incident stemmed from a conflict between two groups of people and resulted in a drive-by shooting, although police did not verify that information.
Family members say Jiles and Andrews were standing outside with friends when a car pulled up and shots were fired. They claim that one of the shooters also died.
While police did confirm those details or provide a motive, they did say there is no one in custody.