Updated 04/27/16 – 11:30 a.m.

CHICAGO (CBS) — For the first time since he was charged with trying to conceal hush money payments to cover up allegations of sexual abuse, former U.S. House Speaker Dennis Hastert has admitted molesting boys decades ago when he was a teacher and wrestling coach in Yorkville.

And in a stunning development at his sentencing hearing, it was revealed one of his victims is the brother of a former political protégé.

Scott Cross, 53, the brother of former Illinois Republican House Leader Tom Cross testified Wednesday that Hastert molested him when he was 17.

Cross said he wanted to be part of the wrestling team Hastert coached at Yorkville High School.

“As a high school wrestler, I looked up to Coach Hastert,” he said.

He said Hastert took him on trips to wrestling camps, and named him captain of the team, but abused him in his senior year of high school in the 1980s.

“He sexually abused me. I was alone in that locker room. I trusted him,” Cross said.

Hastert later apologized when he addressed the court.

“I am deeply ashamed to be standing before you today,” Hastert said, “I know I am here because I mistreated some of my athletes.”

“I am sorry to those I hurt. What I did was wrong. I regret it. I took advantage of them,” he added.

Hastert also apologized to his victims, their families, the government, his friends, and his former constituents for “subjecting them to everything that’s happened.”

When the judge asked Hastert specifically if he sexually abused the boys, Hastert said he doesn’t remember abusing Scott Cross, but admitted abusing other victims.

Scott Cross said he had gone to Hastert because he was concerned about making weight for the team. Cross cried audibly as he described how Hastert pulled down his shorts, and began to massage him and touch his penis. He said he ran out of the locker room, but told no one.

“I was embarrassed. I couldn’t understand what happened and why,” he said.

Cross said he didn’t tell his parents about the abuse until last year, when Hastert was prosecuted over hush money payments to another victim.

“I felt what he did to me was my dark secret,” he said. “Judge Durkin, I wanted you to know the pain and suffering he caused me then, and today.”

Steve Cross’s brother, Tom, was the Illinois House Republican leader from 2002 to 2013, and was a former political protégé of Hastert’s. He ran for state treasurer in 2014, but lost.

Stunningly, Hastert’s defense team acknowledged he called Tom Cross to write a letter of support for him before sentencing. They said Hastert must have compartmentalized the sex abuse he committed, and that’s how he managed to ask a victim’s brother for his support.

Tom Cross issued a statement on behalf of his family shortly after his brother left the witness stand:

“We are very proud of Scott for having the courage to relive this very painful part of his life in order to ensure that justice is done today. We hope his testimony will provide courage and strength to other victims of other cases of abuse to speak out and advocate for themselves. With his testimony concluded, we ask now that you respect Scott’s privacy and that of our family.”

Earlier in the hearing, Jolene Burdge, the sister of another Hastert sex abuse victim, blamed Hastert for her brother’s death in 1995.

Standing two feet from Hastert as she spoke, Burdge said her brother, Steve Reinboldt, told her years ago that Hastert had abused him when he was on the wrestling team at Yorkville High School, where Hastert was a teacher and coach in the 1970s and 80s.

Burdge called Hastert a coward and a sex abuser of children.

“I knew your secret. I hope I have been your worst nightmare,” she said. “You think you can deny your abuse of Steve, because he cannot speak for himself. That’s why I am here.”

She said her brother spent years suffering from “life-long trauma” because of Hastert’s abuse, and blamed him for Reinboldt’s death. Burdge said it would be “impossible and morally wrong” for Hastert go get off easy for his crimes.

Hastert, 74, arrived at the Dirksen Federal Courthouse at 7:10 a.m., nearly three hours before his sentencing hearing. He exited a black SUV and got into a wheelchair to go inside. Hastert was hospitalized late last year after suffering a stroke and a blood infection.

The former speaker has pleaded guilty to violating federal breaking banking laws by withdrawing money in amounts small enough to avoid reporting requirements, in order to pay $3.5 million in hush money to a person identified in court papers only as “Individual A.” Hastert allegedly wanted to ensure “Individual A” stayed silent about being abused by Hastert when the victim was only 14 years old.

Hastert’s attorney, Tom Green, said he would not try to minimize the trauma suffered by the victims of Hasterts’ abuse, but said he thought U.S. District Judge Thomas Durkin should consider the “entire arc of Hastert’s life” before imposing sentence.

“This case has been one of the most tragic and sad cases I have ever encountered,” he said.

Green said Hastert has been “able to reshape his life, commitment to public service” after the abuse he committed.

He also cited a litany of health issues when urging Durkin to sentence Hastert to only probation or home confinement, including a stroke and a blood infection that put him in the hospital at the end of last year.

“He’s humiliated, sits at home, in a wheelchair, unable to care for himself,” he said.

Green said when one of Hastert’s victims, identified in court records only as “Individual A” confronted him in recent years about the abuse, Hastert was “severely frightened and disoriented,” adding that Hastert “made some very poor decisions,” including lying to federal investigators.

Federal prosecutors have said Hastert lied about being extorted by a former student who accused him of sexual abuse. He allegedly told the feds the sex abuse allegations were false and the victims were out to smear his good name.

Federal prosecutors have said Hastert abused at least five boys, but he wasn’t charged with sex abuse – as they would have preferred – because statutes of limitations ran out decades ago. Still, prosecutors wanted to ensure Hastert faced some punishment for his conduct with the victims – all boys 14 to 17 years old – so they chose to file the banking charge against him.

The maximum sentence Hastert could face is five years in prison. Prosecutors had recommended up to six months, while defense attorneys had asked for probation only, citing his health and the steep price they say he’s already paid in public shame.

However, Durkin has hinted he might go beyond the sentence recommendations by using against Hastert the lies he told to FBI agents that he was the victim of extortion.

“The defendant said Individual A was holding him up … extorting him. That’s aggravated. That’s conduct that’s not 40 years old. That’s conduct that’s less than a year old,” Durkin said two weeks ago. “Among the aggravating factors in this case, that’s a big one.”

It was not clear whether Hastert would make a statement or apology at the sentencing hearing.