The 66-year-old shooter who shot dead five people in his neighbourhood in Dunham, Chicago, planned the killing claimed prosecutors on Monday after police found provocative notes in his apartment.
Police retrieved notes that read "Tomorrow!! No Mercy; Without any stupid hesitation!!!", written in Polish inside the shooter, Krysztof Marek's apartment, according to the Chicago Tribune.
Other notes that read "You control it yourself not them!!', "Enough!!", "They have to pay for it!!" and "multiple cryptic letters" were found that addressed issues raised by against him, the prosecutor said.
Officials had stated that the incident "definitely wasn't random," as he had several confrontations with the victims in the past owing to various complaints against him.
"The building condo association was trying to evict Marek for failing to pay both his mortgage and association fees" Assistant State's Attorney James Murphy was quoted as saying.
Identified as a retired truck driver, Marek had stayed in the apartment unit at 6700 block of West Irving Park Road for 15 years. After the hearing on Monday, Judge John Fitzgerald Lyke Jr held Marek for five counts of first-degree murder without bail.
According to official reports, the victims, Tsvetanka Kostadinova and her husband, Ivaylo Popov, both 43, Iskra Pourel-Popova, 65 and David Hanik, 61 were waiting for another family member before beginning their family dinner at around 5.30 pm on Saturday.
Marek entered apartment 2D with his .40 caliber gun and shot dead all four of them. According to the prosecutor, the victims were found collapsed on the floor with their food untouched by the police.
He then went upstairs, opened the front door of unit 3C and shot Jolanta Topolska, 53 in the abdomen. After she yelled "the neighbour" at her son who was in the house, she went downstairs
After Marek exited the front door and headed upstairs, Murphy said, a witness who heard the initial shots saw Marek visibly shaking as he approached Apartment 3C.
Marek entered the unlocked front door and shot Jolanta Topolska, 53, once in the abdomen, the prosecutor said.
Her son saw Marek pointing a gun at her and heard her yell, "the neighbour," she managed to get downstairs through her back door but Marek followed her and shot her at the back of the head.
Marek went back to his apartment and kept his gun on his coffee table and approached the police who had reached the site after residents notified of hearing multiple shots. "I think you're looking for me," he told the police officials. "I did it."
Police found his door open and found the crime weapon and arrested Marek.
In another incident, a three-year-old boy was shot in the head by three gunmen while sitting in a parked car with his mother and two other siblings on Sunday in South Side, Chicago. The boy was admitted to Comer's Children Hospital and his condition is reported to be "stable".
The gunmen are still at large and the Area Central detectives are investigating the case.