Where did the cat come from

Many years ago when I was in the Police I was on duty alone in the station when two little girls knocked on the door carrying a little kitten. They had found it and taken it home but mum didn't want it so she sent them to me
Now dogs were fine,  we had a kennel and food but cats were not 
our responsibility. However I couldn't send them off with it and it was to young to just let it go so feeling sorry I took it home for the night feeling sure he would soon be reported missing
We did have a dog (which I bought from a farm for £5 after I called there one day) but the kitten soon took charge of it and after some month or so it was still with us. Months turned to a couple of years and it was a member of the family. When I took it to the vets he would sit on my shoulder When he passed away we missed this little stranger who was a member of the family