Missing Tuxedo Tabby: Help Find Him!

Tuxedo tabby, desexed He’s kind of skittish and will most likely be hiding, but he’s normally very responsive to his name. He’s wearing a red collar with a bell, but it may have fallen off because it was on loose. He ran out the back door in the morning and my friend was on his way to work and couldn’t stay very long to find him or wait for him to come back. When he’s run off in the past, he alway came back in a few hours. Him being missing for over 24hrs is very unusual