Regarding disagreement with the report of head constable of police station

3 years ago

I lodged theft complaint of material worth Rs 4 Lacs against my wife and my in laws. My wife left my home alongwith elder son on 1st March on invalid grounds. On 20th March I went Mumbai from Kolhapur to see my mother by locking home. Due to covid 19 restrictions, I didn't return Kolhapur due to lockdown and reached Kolhapur home on 1st July , 2020. But, after arrival at Kolhapur it was found that my lock was changed , so I broke it with stone and after entering home it was found that material including golden ornaments were stolen alongwith other material worth Rs 4 Lacs. I came to know that it was stolen by my wife and in laws. So I immediately called local police station and informed about theft. But police station informed me that to come on next day for registration of complaint. I submitted written complaint to local police station against my wife and my in laws. But police did not register it as FIR.
All stolen material was bought by me from my own money and bills are also on my name but the bills were in the cupboard which the wife stolen.
After 15 days, I filed RTI to know status of written complaint of theft. However, they gave vague answer as complaint is under investigation . And informed that head constable is conducting investigation in this case.
As sister of my wife is ACP in the same district and influenced this case. Police neither registered it as non cognizable as well as cognizable offence.
Head constable today gave one false and biased report to me stating that , your wife took material by giving letter to local police station on 5th June, 2020 and as rent agreement was on your wife's name, so she took material by intimating toocal police station. They mentioned that, I lodged theft complaint because of family dispute as wife lodged complaint against me in February month for beating her. But they didn't mentioned that I also filed written complaint against my wife on the same day in February.
As I am not satisfied with the report of head constable as it was no free and fair investigation, can I write disagreement letter to local police station against the said head constable.
How to get justice ?