Jeff Roberson, File, Associated Press
This March 15, 2015 file photo shows St. Louis County Prosecutor Robert McCulloch in Clayton, Mo. A judge Thursday, July 2, 2015 tossed out a push by activists for an independent investigation of a prosecutor's handling of grand jury proceedings in the Ferguson police shooting of Michael Brown, ruling that the effort was "not only logically flawed but contrary to the principles of our criminal justice system."

ST. LOUIS — A judge has tossed out a push by activists for an independent investigation of a prosecutor's handling of grand jury proceedings in the Ferguson police shooting of Michael Brown, ruling that the effort was "not only logically flawed but contrary to the principles of our criminal justice system."

St. Louis Circuit Judge Joseph Walsh III, in a 10-page ruling filed last Thursday, wrote that he reached "the inescapable conclusion" that St. Louis County prosecutor Robert McCulloch "faithfully performed his duty" in connection with the grand jury, "even though some other person may have made the presentation to the grand jury in a different manner."

The grand jury in November declined to indict white Ferguson police officer Darren Wilson in last August's shooting death of 18-year-old Brown, who was black and unarmed. A U.S. Justice Department probe also cleared Wilson, who has resigned.

During two hearings on the matter since April, Walsh had telegraphed his inclinations to reject the lawsuit seeking a special prosecutor to review McCulloch's handling of the grand jury.

An attorney for the activists, Maggie Ellinger-Locke, said Monday her clients would challenge Walsh's ruling to a Missouri appellate court.

"We believe the judge's decision provides prosecutors carte blanche discretion to act arbitrarily in any given case," she told The Associated Press by telephone. "This is not the law, and on this basis we shall appeal."

Ellinger-Locke had argued the grand jury decision was inappropriately influenced by the conduct of McCulloch, whom she insisted "put his thumb on the scale" in Wilson's favor.

Walsh countered that McCulloch had assistant prosecutors run the grand jury proceedings and "wasn't the one asking the questions." The judge also pointed to the Justice Department probe that cleared Wilson, though the federal agency did release a scathing report that cited racial bias and racial profiling in Ferguson policing and in a profit-driven municipal court system that frequently targeted blacks.

"The Department of Justice doesn't take issue with anything that was done (during the grand jury process), and they came to the very same conclusion" as the grand jury, Walsh said during a hearing in May.

The grand jury decision touched off sometimes violent protests in Ferguson, similar to the unrest that occurred in the St. Louis suburb immediately after Brown's death. His shooting also led to demonstrations in other cities and spawned a national "Black Lives Matter" movement seeking changes in how police deal with minorities.

"While the court is sensitive to the raw nature that this incident has provoked around this community and the country at large," Walsh's ruling read, " there simply is no legitimate basis under a strict scrutiny analysis to find that there exists probable cause" that McCulloch acted inappropriately.