I HAD LOST MY IPHONE 6S AND I SURE THAT IT WAS STOLEN BY SOME ONE

Good Evening everyone.hope you doing well.I had lost my i phone and it was fully locked with passcode and my fingerprint .find my phone is on and thief do not know my passcode,apple id and password .I want to confirmed that accidently is their any possibility to unlock or access my photo and all data on my phone for the thief .and now my phone is offline and i was block my sim card also my through the find my phone i was erased my phone but it shown i will work when device will connect to the internet.

but main thing is that accidently if thief put my right passcode without a internet connection then will open my photo or what.because i am sure that if device is connect to the internet it will automatically erased all data.

kindly give me the answer who are very well know about this matter.

Thanks & Regards

jintu gogoi

assam