Workers build new interstate highway bridge over Mississippi River in Missouri.

Workers build new interstate highway bridge over Mississippi River in Missouri.

Workers build new interstate highway bridge over Mississippi River in Missouri.

Memorial setup on the spot in the street where Michael Brown's body lay after he was shot by a police officer on August 9, 2014. (Footage by Joe Raedle/Getty Images)

Memorial setup on the spot in the street where Michael Brown's body lay after he was shot by a police officer on August 9, 2014. (Footage by Joe Raedle/Getty Images)

Memorial setup on the spot in the street where Michael Brown's body lay after he was shot by a police officer on August 9, 2014. (Footage by Joe Raedle/Getty Images)

Memorial setup on the spot in the street where Michael Brown's body lay after he was shot by a police officer on August 9, 2014. (Footage by Joe Raedle/Getty Images)

People protest across the street from the Ferguson Police department in the city where police and protesters clashed over a number of days after the shooting death of unarmed teenager Michael Brown by a Ferguson police officer on August...

Memorial setup on the spot in the street where Michael Brown's body lay after he was shot by a police officer on August 9, 2014. (Footage by Joe Raedle/Getty Images)

Memorial setup on the spot in the street where Michael Brown's body lay after he was shot by a police officer on August 9, 2014. (Footage by Joe Raedle/Getty Images)

Memorial setup on the spot in the street where Michael Brown's body lay after he was shot by a police officer on August 9, 2014. (Footage by Joe Raedle/Getty Images)

People protest across the street from the Ferguson Police department in the city where police and protesters clashed over a number of days after the shooting death of unarmed teenager Michael Brown by a Ferguson police officer on August...

People protest across the street from the Ferguson Police department in the city where police and protesters clashed over a number of days after the shooting death of unarmed teenager Michael Brown by a Ferguson police officer on August...

People protest across the street from the Ferguson Police department in the city where police and protesters clashed over a number of days after the shooting death of unarmed teenager Michael Brown by a Ferguson police officer on August...

Memorial setup on the spot in the street where Michael Brown's body lay after he was shot by a police officer on August 9, 2014. (Footage by Joe Raedle/Getty Images)

Memorial setup on the spot in the street where Michael Brown's body lay after he was shot by a police officer on August 9, 2014. (Footage by Joe Raedle/Getty Images)

MS Boat floating in Mississippi river / St Louis, Missouri, United States

Joplin Missouri after being flatted by a Tornado in 2011

People protest across the street from the Ferguson Police department in the city where police and protesters clashed over a number of days after the shooting death of unarmed teenager Michael Brown by a Ferguson police officer on August...

People protest across the street from the Ferguson Police department in the city where police and protesters clashed over a number of days after the shooting death of unarmed teenager Michael Brown by a Ferguson police officer on August...

St Peter’s cemetery is seen where Michael Brown was buried on August 25, 2014 in St. Louis, Missouri. Michael Brown was shot and killed by a police officer in the nearby town of Ferguson, Missouri on August 9. His death caused several...

Memorial setup on the spot in the street where Michael Brown's body lay after he was shot by a police officer on August 9, 2014. (Footage by Joe Raedle/Getty Images)

St Peter’s cemetery is seen where Michael Brown was buried on August 25, 2014 in St. Louis, Missouri. Michael Brown was shot and killed by a police officer in the nearby town of Ferguson, Missouri on August 9. His death caused several...

Memorial setup on the spot in the street where Michael Brown's body lay after he was shot by a police officer on August 9, 2014. (Footage by Joe Raedle/Getty Images)