Jurors heard from Hunter Biden as part of his trial on gun charges.
The 54-year-old son of the US president is accused of lying about his illegal drug use when buying a gun in 2018, which is a felony, AFP reported.
He is also charged with illegal possession of the firearm, which he only had for 11 days in October 2018.
"No one is above the law -- it doesn't matter who you are or what your name is," prosecutor Derek Hines said in his opening statement during the federal trial in Wilmington.
"Robert H. Biden chose to own an illegal firearm when he was a crack and drug addict," Hines added.
The prosecutor played an excerpt from Hunter's audiobook, "Beautiful Things," in which he talks about his crack use.
First Lady Jill Biden was back in court and had a serious look on her face as the audiobook played.
Hunter Biden's attorney said he was "not on drugs when he bought this gun" and that the weapon was never loaded and never used.
After both sides made their opening statements, an FBI agent took the stand.
A 12-member grand jury was empanelled on June 3, with four alternates.
Joe Biden was not in attendance but said he and his wife were "proud" of their son Hunter.
"As president, I do not and will not comment on pending federal cases, but as a father, I love my son immensely, I believe in him and I respect his strength," Biden said. | BGNES
