frank ernest shepherd , iii of houston , texas was shot dead by police after leading them on a 20 minute high-speed chase .
the chase ended when shepherd crashed into another car .
he then got out of the vehicle and reached into the backseat , and was shot moments later .
no weapons were found in the car and it is not known what shepherd was reaching for .
shepherd was a father of three with another baby on the way .
police are investigating why he fled during a traffic stop .