Unlock a lost Samsung Galaxy S3 Lockscreen

[AC Question]

Hi guys,
I have a really funny problem here, I work at a Go-kart racetrack and I always find lost phones and return them to their owners, but I have this one particular phone which is a Samsung Galaxy S3 I9305.
The owner has a Lockscreen PIN which I can't seem to guess, I just want to find someone in the contacts list to call them but it is not possible, I have kept the phone on for a week so far, and during the past week I have received 3 missed calls from a contact named "Mum".
I have tried inserting the SIM in my Note 4, but there are no contacts saved on the SIM card.
Now I know if I factory reset the phone I will be able to access it, but the last thing I want to do is wipe the owners important data off the phone.
Any advice will be greatly appreciated.

 

[B. Diddy]

Welcome to Android Central! No one's contacted your facility to inquire about the lost phone? Unfortunately, you won't be able to break into the phone. The only thing I can suggest is to carry the phone around with you and actually answer the phone if someone calls.