That's the day the drunken, 42-year-old Perez was found dying on the side of a road in neighboring Bedford.
Bubaris, who has since quit the force, is accused of manslaughter for allegedly hitting Perez and leaving him to die.
The case has brought attention to interactions between police officers and illegal immigrants.
Dwyer is to be cross-examined later Monday as the trial continues in Westchester County Court.
