The jury heard testimony Monday from the woman who was the girlfriend of Ammar Harris at the time of the shooting.
Yenesis Alfonso said she was with Harris the night of the shooting and fiery crash that claimed 3 lives on the Las Vegas Strip in 2013.
Alfonso told the jury that Harris fired shots at Kenneth Cherry and then sped off. Cherry's car then crashed into a taxi, killing the driver and passenger.
Alfonso also testified that Harris was planning to go to Mexico or Cuba.
Harris has pleaded not guilty to three counts of murder.
The trial continues Tuesday afternoon.