If I had two neighbours, Suzuki and Saito, and Suzuki keeps screaming "death to Saito" and shoots at Saito's door every day. Their neighbours know well about both of them. Some of the neighbours cooperate with Suzuki, some stop him from smuggling weapons and the other one, who has the biggest power in the region, cooperate with Saito. I would find it extremely odd if the police did not search the place where Suzuki and his family were shot and Saito did not allow the police to come in the place.
Did the police search Suzuki's place to find out if one of Suzuki's own family killed Mr Suzuki or did the police immediately assume that it must have been Saito?
Also remember that most of the neighbours used to join Suzuki in his insane war against the Saito family.
Plus there used to be Mr Toshiba from the other side of the road, who murdered ALL of the Suzuki's cousins on his side of the road and is still considered a hero by the Suzuki family and most of the other people living in the house.
The biggest power in the region cooperates with Saito, but has only done so for a short time and for some reason tries to be "balanced" all the time, asking Mr Saito please to open the door when the Suzuki family complain that they cannot shoot Saito's children with the door closed.
And the major complaint the police have is that Mr Saito keeps his door closed when being shot at. Plus they condemn the Saito family for not giving free money to the Suzuki family all the time. (Mr Saito already pays the Suzuki family's medical bills and is regularly shot at when he brings over the money.)
Of course there is a back story where the apartments once belonged to Mr Suzuki, and before that to Mr Mitsubishi, and before that to Mr Saito, and after Mr Suzuki they belonged to Mr Turkish Guy and after that to some English dude. All the other apartments in the street are owned by the Suzuki family, who keep the former inhabitants as slaves. Mr Sudanshi and Mr Irakishi (Mr Suzuki's cousins) were the worst perpetrators.
The police hears about it.
Mr Suzuki wants to kill the Saito family and can't because the Saito family keep their door closed.
Mr Saito occasionally shoots back and is a much better shot.
Mr Saito's cousin, Mr Sudanshi, is accused of murdering everyone in the three apartment on his floor and enslaving the people on the floor below. People are FLEEING his part of the house, some to the Saito's apartment, which already houses refugees from all the other apartments.
In the buildings on both sides of the street members of the greater Suzuki family murder and enslave everybody else, except the Saito family who shoot back. And they murder each other. In fact Mr Algarishi (another cousin of Mr Suzuki's) has managed to somehow to end up with one third of his family dead one evening, with no external influence whatsoever.
Mrs Saito complains that she has heard that Mr Saito occasionally murders his own children, and indeed there are often children missing with no explanation.
So the police decide to raid Mr Saito's apartment every two weeks.
And there is nothing wrong with the scenario?