Suicidal Villagers

There's a tribe living in a village in the forest and there are 100 people in it. They are very pious and religious & all want to go to heaven after they die. One day God comes to the village and says to them "there is at least one sinner among you. I will mark the sinner on the forehead. You are forbidden from looking in the mirror or any reflective surface to see if you have the mark. You are also forbidden from telling another person about a mark you see on them. You have to find out on your own if you have the mark, and commit suicide at 10am as soon as you know you have the mark. If you do so you'll go to heaven, otherwise you'll go to hell." God then marks everyone in the village (without their knowledge) and leaves. What happens next?