Former Penn State assistant football coach Jerry Sandusky leaves the Centre County Courthouse after the first day of his child sex abuse trial in Bellefonte.

Bellefonte - The first witness called in the Jerry Sandusky child sex abuse trial testified on Monday that the former Penn State assistant football coach treated him like “his girlfriend” when he was a young teenager, showering together and engaging in oral sex.

The testimony by the 28-year-old man came after jurors heard opening statements from prosecutors and the defence as the closely watched trial got under way in Pennsylvania.

The prosecution branded the 68-year-old Sandusky a “predatory paedophile” and said his young victims remained silent only out of fear and shame. Defence lawyer Joe Amendola told the seven women and five men of the jury that Sandusky was a naive man filled with love and affection for young people.

“Jerry Sandusky, in my opinion, loves kids so much he does things that none of us would ever think of doing,” Amendola said.

Sandusky faces 52 counts of sexual abuse against 10 boys. If convicted, the former Penn State football defensive co-ordinator could be sentenced to more than 500 years in prison.

The opening witness called by prosecutors told jurors he met Sandusky when he was 13 years old, in 1996 or 1997. He said his relationship with Sandusky evolved from showering together after workouts at Pennsylvania State University facilities, to the coach putting his hand on his leg while driving in a car, to oral sex, as well as being lavished with gifts.

“It was basically like I was his girlfriend. It was the way I would treat my girlfriend,” the man testified.

A handwritten letter allegedly sent by Sandusky to this witness was placed into evidence on Monday. “I know that I have made my share of mistakes,” it read. “There has been love in my heart. My wish is that you care and have love in your heart.”

Sandusky is accused of using the Second Mile, a charity he founded in 1977, to prey on needy young boys. The charity said last month it was closing because contributions had dried up.

In a flurry of motions filed on Monday, another defence lawyer, Karl Rominger, said he would likely call an expert witness to explain that a psychological problem suffered by Sandusky, known as histrionic personality disorder, led him to write “love letters” to his alleged victims even though he was not trying to lure them into sex.

Prosecutors allege Sandusky had physical contact with the boys, known in court documents as Victims 1 to 10, that ranged from tickling and a “soap battle” in Penn State showers to oral and anal sex.

Eight young men are due to testify in Centre County Court in Pennsylvania about how Sandusky befriended and sexually abused the boys over a 15-year period, according to prosecutors. The men, now aged 18 to 28, are being identified publicly for the first time in court.

In his opening statement, prosecutor Joseph McGettigan III called Sandusky a “predatory paedophile” and urged the jury to listen to his alleged victims in the case, now men, as though they were children.

McGettigan added that he would press the witnesses for details in the lurid case only because the jurors' needed to hear them. “I must ask, and they must answer,” McGettigan said.

Putting up pictures of eight of the 10 alleged victims on a courtroom screen, while occasionally jabbing a finger toward Sandusky, McGettigan told jurors that eight had remained silent until now out of humiliation, fear and shame.

As the prosecutor spoke, the white-haired Sandusky sat silently, hunched forward with his back to the packed courtroom, as ceiling fans whirled overhead.

Rominger said he believed the prosecution planned to use the notes attributed to Sandusky to try to show he was grooming his victims for abuse.

“The goal of a person suffering this (histrionic personality) disorder in writing those letters would not necessarily be to groom or sexually consummate a relationship in a criminal manner, but rather to satisfy the needs of a psyche belaboured by the needs of the disorder,” Rominger said in the motion.

Amendola called his task of defending Sandusky a difficult one, given the resources of the state and a “tidal wave” of negative publicity about the case. “This is a daunting task. This is like looking up at Mount Everest from the bottom of the hill, it's like David and Goliath,” he told jurors.

Amendola indicated Sandusky could take the witness stand, telling jurors that the former coach would tell them about his youth and how taking showers with other people had been common for people of his generation growing up in Washington, Pennsylvania.

Amendola also hinted that the accusers could be out for money, saying that six of the eight identified accusers had taken the step of hiring civil attorneys.

The abuse charges shook the university and prompted the firing of revered football coach Joe Paterno and university President Graham Spanier last November. The allegations brought an ignominious end to the career of Paterno, who recorded more wins in major college football than any other coach. He died of lung cancer in January.

The trial has brought a flood of media to Bellefonte, a town of 6 200 people 16km northeast of State College, the location of Penn State's main campus. The lawn and side streets around the courthouse were filled with reporters, cameras, news vans and tents. - Reuters