Okay, so imagine you have a friend who is a police officer, and his job is to solve crimes and catch bad guys. One day, he tells you about a letter that he received in the mail. The letter was from a man who said he was going to kill himself because he felt really sad and didn't want to live anymore.
But here's the thing: the man said that he was important and had some secrets that could hurt other people. He also said that the police and the FBI were watching him and making his life worse. So your friend, the police officer, got worried and took the letter to his boss, who works for the FBI.
The FBI is like the super special police; they solve really big crimes that happen all over the country. So when they read this letter, they got really worried too. They thought that maybe the man who wrote it had done something really bad and was feeling guilty about it. Or maybe he was part of a group of bad guys who were planning to hurt other people, and he was trying to warn them.
So the FBI started to investigate, which means they tried to find out more information about the man who wrote the letter. They looked at his background, talked to his friends and family, and tried to figure out what he might be planning to do. They also kept an eye on him to make sure he didn't hurt himself or others.
Eventually, the man did kill himself, just like he said he would in the letter. After he died, the FBI found some more letters and notes that he had written, which confirmed that he was feeling very sad and scared. They also found out that he didn't actually know any big secrets or have anything to do with any crimes.
So while the FBI was worried at first, they realized later that the man was just very unhappy and needed help. They were sad that they couldn't do more to save him, but they hoped that his letter would help other people who are feeling sad to get the help they need.