Jurors heard from a DNA expert Tuesday in the trial against a man accused of killing a young boy and injuring a young girl in a June 2014 stabbing.

Daniel St. Hubert is accused of stabbing 6-year-old PJ Avitto and then-7-year-old Mikayla Capers inside an elevator at the Boulevard Houses in East New York. Avitto died of his wounds, while Capers survived and went on to testify in the trial.

On Tuesday, a DNA expert testified that St. Hubert's DNA was found on a knife recovered from the scene.

The defendant's attorney, Howard Greenberg, called DNA "junk science" during opening statements nearly two weeks ago. Since then, numerous responding officers and a crime scene investigator have testified. Jurors have heard the 911 call and heard from witnesses who say they saw St. Hubert trip while walking away from the building, appearing to be in a hurry.

MORE: 911 audio call - Warning: Please note that some may find this audio disturbing.

The most emotional testimony came from Capers herself. The survivor, who is now 11 years old, pointed out St. Hubert in the courtroom as the "bad" or "mysterious" man who attacked her and Avitto. Greenberg has called her a liar.

On Monday, the courtroom was sealed off for about 15 minutes because St. Hubert wanted to address the judge directly. The transcripts of that conversation were released Tuesday after requests by lawyers from other media outlets. In them, St. Hubert tells the judge that he is innocent and that he's being set up. After listening to his reasoning, the judge explains to him that he does have a right to testify in front of the jury and in front of the whole court, and that it's a decision he can make after consulting with his attorney.

It was requested that the information be sealed because the prosecution was concerned that the media would report on what was said, essentially putting out the defendant's defense without him having to take the witness stand.

Greenberg spent hours Tuesday questioning the DNA expert who testified that there were at least two DNA profiles on the knife, but the majority sample belonged to St. Hubert. A profile could not be determined for the minority sample. Greenberg questioned if DNA could exist somewhere that someone had never been.

On Wednesday, jurors are expected to hear from the medical examiner, the lead investigator in the case and Capers' great-grandmother. Closing arguments be delivered on Thursday.