The jury will decide if Moussaoui, the only man to stand trial in connection with the September 11 attacks, will face execution or life in prison.
Moussaoui, last week claimed he would have flown a fifth hijacked jet into the White House on September 11, 2001, had it not been for his arrest weeks earlier.
The prosecution laid out pictures of burned corpses of those who perished when American Airlines flight 77 struck the Pentagon, killing about 189 people.
Painful testimony
Chinese-born doctor Rui Zheng gave emotional testimony on Tuesday expressing her guilt for changing her parents’ flight reservations at the last minute to American Airlines flight 77 on September 11, 2001.
Prosecutors showed pictures of Ms Rui’s parents, Shuying Yang and Yugang Zheng posing before the US capital's Washington monument obelisk.
Ms Rui, a 34-year-old cancer researcher, told the court the couple had been due to go home after a one-year vacation on September 10, 2001.
But the night before they were due to go home Ms Rui made a late-night switch and booked her parents on the plane which later struck the Pentagon.
"If I had not changed the flight, everything would have turned out differently," said Ms Rui. "They would still be alive and enjoying their lives, and I feel very responsible for that ... that feeling of guilt will never go away," she said in halting English.
Call for shoe bomber to appear
Prosecutors have said that Moussaoui, a Moroccan born French national and alleged Al-Qaeda conspirator, withheld information to authorities which could have prevented the attacks.
Lawyers for Moussaoui meanwhile, called on the court to subpoena convicted British "shoe bomber" Richard Reid, apparently hoping his testimony would undercut their client's claims of a key role in the attacks.
Moussaoui claimed two weeks ago that Reid would have been part of his crew that had planned to fly a plane into the White House.
Prosecutors later filed a sealed motion opposing the request.
Judge Leonie Brinkema made no public statement, but issued a writ calling for an unnamed person to be delivered to testify.