(Reuters) – The 41-year-old adopted son of Jerry Sandusky, the former Penn State University assistant football coach convicted of sexually abusing young boys, pleaded guilty on Friday to soliciting two teenage sisters for sex, Pennsylvania prosecutors said.

The guilty pleas by Jeffrey Sandusky came one week before he was set to go trial on allegations that he sent lewd text messages to the underage girls asking for sex and naked photographs, the Center County District Attorney’s Office said in a statement.

The younger Sandusky pleaded guilty to 14 charges, including solicitation to commit sexual assault on children and unlawful contact with a minor, prosecutors said.

Under the plea agreement, Sandusky would serve three to six years in prison but could be sentenced to a longer term of up to eight years, prosecutors said.

A telephone message left for his attorney, Lance Marshall, was not immediately returned.

Jerry Sandusky, 73, was convicted in June 2012 on 45 counts of sexually abusing boys over several years while he was an assistant coach for the vaunted Penn State football program.

The scandal rocked the university, leading to jail sentences for three high-ranking school officials convicted of child endangerment for covering up the abuse, which allowed more boys to be victimized. Legendary head football coach Joe Paterno, who was accused of complicity in the cover-up, was ousted from his post and died months later.

The university has paid more than $90 million to settle claims filed by victims.

Police launched an investigation into the younger Sandusky when a 16-year-old girl told police that he sent her text messages asking her to send him nude and sexually explicit photographs, authorities said.

A second victim, who was 15 at the time, then came forward to report that Sandusky had solicited her to perform oral sex on him, also via text messages.

At the time of Sandusky’s arrest in February, Pennsylvania State Police said in a criminal complaint filed in Bellefonte, a town near Pennsylvania State University’s main campus, that the girls were the daughters of a woman Sandusky had been dating.

After serving his sentence, Sandusky will be classified as a “highest tier” sex offender and must register with police with his address, place of employment and other information every three months for the rest of his life, prosecutors said.

District Attorney Stacy Parks Miller said prosecutors were prepared to go to trial, but Sandusky pleaded guilty to all the charges.

“This outcome also ensures the victims need not suffer the trauma and re-victimization of testifying at trial,” she said.