Let's say you're among a group of people and someone forgot their wallet and asked you to loan them some cash to get a cup of coffee. You let them know you didn't have enough cash with you. A few hours later you are ready to get lunch but realize your wallet is missing. You had left it in your bag which you didn't have with you only once since you were with the group and that was to use the restroom. After you've ruled out that you didn't leave it at home and it's not in your pockets, who is the first person you'll be suspicious of, is it the person who asked you for money? We could even go deeper and say, someone was admiring your watch and even asked where you bought it. An hour later your watch is missing. Who will you suspect, the same person that was admiring the watch? Not because someone asked you for money and yours go missing after means they took it.
Truth be told, it's best to check and double check before accusing someone regardless of how things appear. We misplace things at times. Not saying that people are always innocent in situations such as these but think of how you would feel if you're accused of something you didn't do, especially stealing. In some situations we cause people to lie to us because when they tell us the truth, we do not accept it. Our minds are already made up which will cause us to believe a made up version of events rather than the truth.
How do you feel after accusing someone of taking something then finding it somewhere you forgot to look. You know in your heart that they would not have had access to take it from there. After you have found what you thought was stolen, do you go back and apologize? While apologies are great something like this leaves a stain on a person. Maybe you told a few people how you were robbed and even named names but forgot to mention that you found it. They are left thinking of this person as someone who cannot be trusted and may pass this untruth on to others. It spreads and this individual's character is ruined. Let us remember that the truth always comes out.