Five men and four women have been selected to be jurors in the Pennsylvania trial of Jerry Sandusky, the former Penn State assistant football coach charged with child rape.

About 220 potential jurors reported for duty Tuesday, after the court whittled the number to about 600 based on answers to questionnaires sent to prospective jurors' homes. Of those, about half were sent home and asked to return Wednesday.

"We are now making good progress," Judge John Cleland said late Tuesday afternoon.

Twelve jurors and four alternates will eventually be selected.

Sandusky, 68, has been under house arrest since being charged with sexually abusing 10 boys for at least 15 years. Prosecutors allege he met some of his accusers through Second Mile, a charity he created for underprivileged children.

He has pleaded not guilty to the charges. He and his attorney, Joe Amendola, were in attendance Tuesday.

Opening statements are expected to begin Monday, the judge said, and the trial is likely to last about three weeks.

Sandusky supposedly wrote love letters to one of his alleged victims, Victim 4, ABC News reported late Tuesday. They will be read into testimony, ABC said.

When asked by CNN about the report, the attorney for Victim 4, Ben Andreozzi, said he expects that letters from Sandusky to his client will be introduced at trial, but declined to comment on their content.

Gifts Sandusky allegedly gave to Victim 4 may also be introduced as evidence by prosecutors, according to a source close to the case. Those gifts could include golf clubs and football jerseys, the source said.

A source close to another alleged victim, Victim 1, said Victim 1 received birthday cards and notes from Sandusky, but that they were not sexually explicit in nature. They included statements such as, "I love you," but did not contain anything overtly sexual, that source said.

Authorities allege that Sandusky abused some of the boys on the Penn State campus. The case has shaken the university, raised questions about its response to the allegations and drawn criticism from those who claim Penn State put its reputation ahead of protecting potential child victims.

University President Graham Spanier and iconic head football coach Joe Paterno lost their jobs soon after Sandusky's arrest amid criticism that they did not adequately handle the matter when allegations involving Sandusky arose years earlier. Paterno died of complications from lung cancer in January.

Mike McQueary, a former graduate student considered to be a key witness in the Sandusky case, has testified that he alerted Paterno in 2002 that he'd seen what appeared to be Sandusky sexually assaulting a boy in a shower in Penn State's athletic facilities, an allegation that authorities didn't learn of until years later.

Paterno apparently told the university's athletic director, Tim Curley, but no one notified police. Curley and Gary Schultz, Penn State's senior vice president for finance and business, are now facing felony charges of perjury and failing to report the allegations to authorities.

Prosecutors said later that the McQueary incident took place about a year earlier than was originally alleged, causing defense attorneys for Curley and Schultz to argue that one of the charges should now be dropped. Both of them have pleaded not guilty, and their attorneys have said that prosecutors "charged this case before (they) knew the facts."

Potential jurors were asked Tuesday about their relationships with Penn State, local law enforcement and Second Mile, and whether they had contributed to any of those entities. Several reported knowing Sandusky or his wife, while others said they had volunteered at Second Mile. Others said they were current or former Penn State employees.

Prosecutors plan to call more than 50 witnesses during the trial, and the defense plans to call about 100, including Jay and Sue Paterno, Joe Paterno's son and widow; McQueary; his father, John; and Spanier, among others.

The prosecution is preparing witnesses for their testimony next week, according to several sources close to the case. The 28-year-old man known as Victim 4 is expected to testify first, with Victim 1, who started the investigation by coming forward in 2008 and alleging years of abuse, to follow, the sources said.

McQueary and his father were told to be in town and ready to testify next Wednesday or Thursday, one of the sources said.

Cleland told members of the jury pool that jurors in the case will not be sequestered, saying he will trust them not to read newspapers or follow the case online.

He told the prospective jurors that after he speaks with them, groups will be taken to another room for questioning and then to a different room for more questioning from the judge and attorneys.

If they are selected, he said, they will be taken to a different room. "We're using all the rooms," Cleland quipped as pool members chuckled.

Sandusky listened intently to the judge as he spoke to the jury pool, also chuckling at times. But he looked down when the judge discussed the charges against him.

As jury selection in the case began Tuesday, Penn State released a statement, saying, "The acts that Jerry Sandusky is accused of committing are horrible and if proven true, deserve punishment."