CHICAGO (CBS) — Hazel Crest police said investigators are still trying to find the person or people responsible for gunning down a father and his two young daughters in July.

Police Chief Mitchell Davis said detectives have an idea about the motive for the killings, but he doesn’t want to make that public yet. However, police still are not close to solving the murders of 39-year-old Dionus Neely, 10-year-old Elle Neely, and 3-year-old Endia Neely.

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The three were slain when bullets were fired into their home on the 2400 block of Crescent Drive around 2:30 a.m. on July 2.

“Because of there being children involved, there were people who did come forward who normally may not have come forward; but even though they did come forward, just as it was asked a little while ago, a lot of people that come forward aren’t necessarily comfortable with coming forward to the extent of sitting on a witness stand, or something like that. So that’s one of the roadblocks that we’re running into,” Davis said.

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He said detectives continue to wait for a big lead that will point them to the killer or killers.

“A lot of times, what will happen is, down the road, once the smoke clears, somebody will get arrested or something will happen to somebody, and they’ll say ‘You know what, I’m going to let the police know what I know,’ and we’re just praying that that’ll happen sometime in the near future,” Davis said.

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The chief said a $5,000 reward is being offered for information that leads to an arrest and conviction in the case.