Genesis 42:13

The youngest brother, who was with their father, was Benjamin. And when they said, ‘one brother is dead’, they meant Joseph. And Joseph knew that they meant him. The brothers had persuaded their father Jacob that Joseph was dead. (See Genesis 37:31 and comment.) But, when they did that, they were lying to their father. They did not actually know whether Joseph was dead. But they believed that he was dead.

v14 But Joseph said to them, ‘What I said is true. You are spies. v15 But I will test you. You shall not leave this place unless your youngest brother comes here. That is as certain as that *Pharaoh lives. v16 Let one person go. Let him bring your brother, while you remain in prison here. I will test your words. I will discover whether you say true things. If you do not, you are certainly spies. That is as certain as that *Pharaoh lives.’ v17 And Joseph put all the brothers together in prison for 3 days.