Lost Cat: Black Nose Mark, White Chest

He has a black mark on his nose which looks like a moustache. He has black ears but a white chest and arms. He is mainly black on top but white on his stomach and under area. He is anxious around people and especially cars. He left at his usual routine on Sunday 15th February at 6am for neighbourhood walks but did not return by his usual 11am for breakfast. He has not returned since. This behaviour is completely unlike him and he has not done anything like his before. We suspect that, as he does not enjoy wearing a collar and frequently loses them, a welcoming and unsuspecting family has believed him to be a stray (though he is well fed and healthy) and taken him in, but he is not.