CHICAGO — A 19-year-old man charged with the fatal shooting of four people at a Chicago fast food restaurant last week may have been seeking to avenge the murder of his father a day earlier, police said Wednesday

Police took Maurice Harris into custody Tuesday and charged him in the fatal shooting that authorities believe was a gang-related attack. The four killings were among eight homicides that occurred late Wednesday and Thursday night in the city’s South Shore neighborhood.

Harris is alleged to have carried out the attack the day after his father, Jerry Jacobs, was gunned down as he walked in the neighborhood, police said. Jacobs was a documented gang member, and Harris had an extensive rap sheet as a juvenile.

Police Cmdr. Brendan Deenihan said that Harris has not confessed to the killings at Nadia Chicken and Fish restaurant, but was identified by several witnesses as the gunman.

"I don't have the motive for why Jerry Jacobs was killed," said Police Cmdr. Brendan Deenihan. "But Jerry Jacobs was murdered and (less) than 24 hours later his own son goes and kills four people. So, obviously those two incidents are related."

Police are also trying to determine if the quadruple homicide and the killing of Jacobs are tied to the fatal shootings of a 27-year-old man and a 23-year-old woman that occurred hours after Harris allegedly carried out the attack at the restaurant. All but one of the victims in the violence had ties to either the Gangster Disciples and Black P Stones street gangs.

Investigators have determined that the fatal shooting of a pregnant 26-year-old woman in the same neighborhood that also occurred on Thursday was not related to the other three incidents.

In the quadruple homicide, four male victims were found in or around the Nadia Fish and Chicken restaurant, according to police.

Police said a male suspect approached the restaurant and fired shots. When officers arrived at the scene, they found two of the victims — Emmanuel Stokes, 28, and Edwin Davis, 32 — inside the restaurant. Dillon Jackson, 20, was found dead outside the restaurant. His brother, Raheem Jackson, 19, was found in a nearby yard. The Jackson brothers' mother worked in the restaurant where they were shot.

The nation’s third-largest city has tallied more than 140 murders in 2017, nearly the same number of killings as the city saw at this point last year. Chicago finished 2016 with more than 760 murders, making it the most violent year for the city in about two decades.