U.S. Rep. Keith Ellison supports a Congressional Black Caucus letter urging the Justice Department to conduct a complete, stand-alone investigation of the Aug. 9 fatal shooting of an unarmed black teenager by a police officer in Ferguson, Mo.

The caucus signed sent a letter to Attorney General Eric. H. Holder Jr., that expressed gratitude for the Justice Department investigation already underway regarding the incident, in which a Ferguson policeman shot and killed 18-year-old Michael Brown.

Police have said the teen tried to take an officer's gun, but at least one witness said the teen was shot without cause.

"Press reports suggest that Mr. Brown's shooting may be symptomatic of larger racial tensions in Ferguson," the letter to Holder read.

"We ask the Department to dedicate sufficient resources to investigate the legal and civil rights ramifications of the shooting and surrounding circumstances," the letter writers said.

"First, the St. Louis County Police Department may not be the most objective or credible body to investigate civil rights matters involving law enforcement given evidence of racial profiling in the past year," they continued. "Second, only the federal government has the resources, the experience, and the independence to give this case the close scrutiny that the citizens of Ferguson and the greater St. Louis area deserve."

Ellison used his Twitter account earlier this week to call for a "full, transparent investigation into the shooting of Michael Brown" and added that "Thoughts and prayers are with his family."

CBC letter on DOJ inquiry Into Michael Brown death