Bellefonte, Pennsylvania (CNN) -- Jerry Sandusky's writings in a 2000 memoir about the difficult relationship with his adopted son, Matt, are similar to several letters he wrote to a boy now known as alleged victim No. 4.
Matt Sandusky, now 33, came forward this week as his father's child-sex trial drew to a close to say he, too, had been molested by Jerry Sandusky and was willing to testify.
Matt, like No. 4 and many other of Sandusky's accusers, got to know the former Penn State defensive coordinator through The Second Mile charity Sandusky founded in 1977 for at-risk kids.
No. 4, the first of eight alleged victims to take the stand in Sandusky's trial, mentioned Matt in his testimony, describing an awkward moment in the showers with the boy and his father.
"One time (Sandusky) and me and his son, Matt, had gone to play racquetball," No. 4 recalled. "Matt went into the shower, and then me and Jerry came in. (Jerry) started pumping his hand full of soap, like he was going to throw it. Matt got out, he went to another shower." The witness was asked to describe Matt's expression.
"Nervous," he said.
The exchange raised eyebrows in the courtroom, but soon was lost in an avalanche of dramatic testimony.
Sandusky's relationships with both boys followed a familiar pattern, according to testimony and the memoir. They began as rescue missions, expectations were raised, and then they crumbled in disappointment and estrangement.
The letters written by Jerry Sandusky to No. 4 are in the jury's hands and may well hold the key to some of the most serious charges against him.
In the letters, he sometimes assumed the voice of a mentor, providing words of inspiration and encouragement. But he could also appear needy, scolding and manipulative.
At times, he sounded like a love-struck teenager weathering that first painful breakup.
Judge John Cleland allowed reporters to view copies of the letters and other trial exhibits on a big screen in the courtroom after the jury retired for deliberations. Only parts of the letters had been read aloud during the trial.
Sandusky, 68, is charged with 48 counts and accused of molesting 10 boys over 15 years. He has denied the charges but did not take the stand at his seven-day trial.
Prosecutor Joseph McGettigan alleges Sandusky used The Second Mile to troll for preteen boys to molest. He called Sandusky "the perfect predatory pedophile," saying he groomed victims for sexual encounters in Penn State's locker room showers, hotel rooms and a waterbed in the basement of his home.
CNN does not disclose the names of alleged sexual assault victims; Matt Sandusky's name is being used because he made it public through his attorneys.
"This has been an extremely painful experience for Matt," his lawyers, Andrew Shubin and Justine Andronici, said in making the announcement about Matt's allegations. The lawyers also represent two other Sandusky accusers, referred to in court records as alleged victims No. 3 and No. 7.
In "Touched: The Jerry Sandusky Story," Sandusky wrote that Matt was 7 or 8 when he showed up at The Second Mile. He said the boy "became an instant challenge for me."
As with the boys who testified at his trial, Sandusky began as a mentor and father figure to Matt -- and then the relationship intensified and ultimately soured, according to the book. Sandusky became Matt's foster parent, and then his adoptive parent.
For a while, Sandusky says in the book, Matt turned his life around, but the relationship between the two has been strained in recent years. Matt has had his share of troubles.
According to court records cited by the Harrisburg Patriot-News, Matt Heichel, as he was then known, left the home he shared with his mother, brother and sisters to live in foster care with the Sanduskys when he was 11. But Matt attempted suicide a few months after moving in with the Sanduskys. He also ran away from the Sandusky home and was accused of stealing.
Matt's birth mother has accused Sandusky of stealing her son from her; in his book, Sandusky characterized her as "jealous."
Later, Matt attended Penn State and was an equipment manager for the football team, according to Jerry Sandusky's book. He married in 2003, and the relationship with his adoptive parents grew strained. That year, Jerry called police to his house and alleged Matt was trespassing.
Matt's estranged wife told the Patriot-News that Matt would throw up after talking to his adoptive father on the phone. Later, she fought in court to keep her son away from Jerry Sandusky when Matt moved back in with his parents after their marriage hit the rocks.
The eight young men who testified against Sandusky said he approached them, usually in the swimming pool, during their second year at the Second Mile program. All were fatherless boys, like Matt, and many had behavioral problems.
Sandusky used some boys simply for sex, McGettigan said in his closing argument. But others, particularly Nos. 1 and 4, were drawn into relationships, the prosecutor said.
"Creepy love letters" is the way No. 4 described Sandusky's notes to him. The undated, handwritten letters -- some several pages long -- seem to tell the story of a declining relationship.
No. 4 testified that most of them arrived when he began to withdraw and avoid Sandusky as he grew up and developed other interests, including a girlfriend.
Defense attorneys countered that the letters are symptomatic of a personality disorder that made Sandusky immature, prone to drama and unrealistic about his personal relationships. An expert for the prosecution disagreed, saying Sandusky showed signs of a "psychosexual disorder."
In the letters, Sandusky portrayed himself as a plain, simple man who cared. In one, he compared himself to the movie character Forrest Gump.
"As you know, I am very emotional and kind of let everything out!" Sandusky wrote No. 4, then 15 or 16. "I'm not good at hiding my feelings. I have many 'Forrest Gump' qualities, and I thought a lot about that movie as I was driving home. As you would expect, I cried at that movie."
He wrote that he wished he could be more like the movie character. "I remembered Forrest and how he was so naïve (oblivious to the world) and not very smart. He was so happy that he wasn't caught up in being anything other than a caring person."
He took on the voice of an adviser, continuing:
"As you go through life, you may have moments when you think that there is a lifestyle out there somewhere that is the answer ... I hope that in the back of your mind will be a memory of simple times, hopefully laughter, joy, and warm smiles. Try not to ever forget all of those who care. Try to remember canoes, squirt guns, water balloons, fighting outside, miniature golf, Polish soccer, basketball, racquetball, football, swimming, studying, lifting, working, golfing, volleyball, laughing, hurting, arguing, crying, caring, and so much more fun."
He pointed out that Gump stayed loyal when others let him down "because he didn't know any better." Sandusky signed his missive, "Forrest Jer."
Another document, titled "The B-J Story," describes a relationship that blooms and then falters.
"Very few people know about this story and probably less care. I guess that I'm writing it for me. I'm Jer," he began. He wrote that the relationship grew after his own father died.
"It was a difficult time for Jer because he had lost his dad. Jer and his dad shared so much, did many things together. (No.4) comes along and he and Jer seem to enjoy the same experiences. Both seemed to be in need. They loved playing games, competing, singing, laughing, sharing experiences, just being themselves."
He continued, "Jer became attached to (No. 4) and always will be. He and Jer played Polish Soccer, wrote papers together, rode a four wheeler even though Jer was scared to death, studied in the playground, roller skated, ice skated, jet-skied, went to a bowl game, spent days at football and soccer camp, canoed, traveled, and more.
Things got rocky, he added.
"There were ups and downs. There were arguments, fights, they cared! No matter what, there was a connection that would help them last through these difficult times."
But something came between them, "a dark cloud" that "inch by inch" took over and "smothered sensitivity and love."
He ends the letter with a plea: "Jer may not be worthy, but he needs a 'best friend.' It doesn't look real good."
His tone is scolding, accusatory, in yet another letter to No. 4:
"I write because of the churning in my own stomach when you don't care. I write because I still hope that there will be meaning to the time we have known each other ... We seem to be a convenience. When it is inconvenient or a better deal comes along, you leave a trail of broken promises. Commitments seem to be meaningless."
"You are able to bounce from person to person, object to object. You seek happiness through control, domination, and what satisfies the moment. You have to hit the home run, swing for the fence. You don't understand or choose not to worry about loyalty, commitment, or caring. The motivation is to get what you want regardless of others."
Sandusky also grew frustrated with Matt's ups and downs, he wrote in "Touched." At one point, Matt was considering returning to his mother's house; at another, he talked about quitting high school.
"I didn't want to lose him to whatever other fates might have awaited him," Sandusky wrote, "so I kept trying and trying to pull him in."
It did not go well at first. Matt had gotten into trouble with the law, and prosecutors were pushing to send him away.
"Subconsciously, I started to withdraw from Matt because I just couldn't deal with the hurt anymore," Sandusky wrote. "I felt we had done everything we could for Matt, and the end of our relationship was approaching. I told him there was nothing left and that we had played our last card. I told him if he did something wrong again, he would be out of our control, and there would be nothing more I could do for him."
Then came the breakthrough Sandusky wrote he had hoped for. Matt signed a behavior and achievement contract for a Second Mile program called "Keep Climbing." It included a list of expectations and rewards.
"I ought to punch you in the nose," Sandusky said, hugging him. "You drive me nuts!"
Acccording to testimony, No. 4 signed similar contracts. A Second Mile official testified that they weren't genuine, and No. 4 said he believed Sandusky was using them to stay in his life.
"I signed them to shut him up."
CNN's Wayne Drash contributed to this report.