The jurors have certain information concerning the defendants past behavior and police record; what is that information?

The defendant has a troubled past. His mother is dead, his father served time in jail. There is also the testimony of witnesses.... the old man who heard the boy threaten his father, the boy bought a knife the night of the murder that was identical to the murder weapon, a woman across the street claims to have seen him stab his father, and psychologists have administered tests that proved homocidal tendencies.