Seven people were shot, including two people who died. The dead have been identified as 38-year-old Emmitt Suddoth and 39-year-old Brian Glass, both of Chicago.
The shooting happened just before 2 a.m. Sunday.
When emergency responders arrived on the scene they discovered seven people in all had been shot. Five were inside the club, and another two were on the street.
Of those killed, Glass was already dead on the scene and Suddoth was pronounced at Stroger Hospital.
This happened at the Hawks Motorcycle Club, located in the 100-block of West 75th Street in the West Chatham neighborhood.
Chicago police said that the injured include three men and two women, all of them transported in serious to critical condition to three different hospitals that include Stroger, Mt. Sinai, and Advocate Christ Medical Center in Oak Lawn.
One witness said he heard something strange from across the street.
"Was just in the house playing games with the kids, and we heard four or five shots. And after that we heard the police and ambulance come," said the witness who only identified himself as D.B.
Suddoth's family say they can't believe he's gone.
"We're in mourning at this time. Emmitt was a very loving person, father, and caring," said cousin Suzette Brown.
Relatives say the Chicago entrepreneur and other members were at the Hawks Motorcycle Club for the group's monthly club meeting and party.
"That was his life -- motorcycles -- and he was the president of the club and just was a fun-loving person," said Finley Smiley, victim's brother-in-law.
Investigators say the attack may have been sparked by a verbal altercation between the shooter and one or more members of the club.
Suddoth's neighbors were shocked by his death.
"It's not like 'the bad boys.' These guys are working people, just common people," said Allen Beaton.