Cook County Crime Stoppers has doubled its reward offer to anyone who can provide information leading to an arrest in a mass shooting that killed three people this month in Chicago Lawn.The reward has been increased to $20,000, up from the initial $10,000 offered a week after the Dec. 2 shooting at a home in the 3500 block of West 59th Street.Eight people were wounded — four men and four women — in the afternoon shooting, Chicago police have said.Two men, 28-year-old Jon Carlos Blancarcer, and 32-year-old Osmer Angel Ferrer Oria, were pronounced dead at the scene. A third man, Hector M. Sajo, 26, died at Advocate Christ Medical Center in Oak Lawn, according to police and the Cook County medical examiner’s office. Related Mass shooting victims were celebrating at Little Village club before 3 were killed, 5 wounded in Chicago Lawn $10,000 reward offered for information leading to arrest in Chicago Lawn mass shooting Witnesses told police they were having a birthday party when a fight erupted in the hallway of the basement, and “moments later, multiple gunshots were heard,” according to a police report obtained by the Sun-Times.According to the report, witnesses told investigators that after leaving a club in the 2500 block of South Kedzie Avenue, the group wanted to “continue the party” and relocated to the house on 59th Street where a popular Venezuelan deejay was performing.The report said the shooter or shooters may have arrived in a green Subaru and tried to flee in it after the shooting, but they fled on foot north on St. Louis Avenue.Police found a “gun box” on the rear floorboard, and the Subaru was towed to an auto pound for processing.Officials have been unable to provide a potential motive or any other information.Cook County Crime Stoppers asks anyone with information to submit an anonymous tip at (800) 535-7867 or by email to [email protected]. Anonymous tips can be left with Chicago police at (833) 408-0069 or cpdtip.com.