CLAYTON, Mo. — A judge on Friday deferred ruling on a request by activists for an independent probe of a prosecutor's handling of grand jury proceedings in the Ferguson police shooting of Michael Brown, but he again gave strong indications he might toss the lawsuit.

St. Louis Circuit Judge Joseph Walsh III heard an hour of arguments over the lawsuit by four activists pressing for a special prosecutor to review St. Louis County prosecutor Robert McCulloch's handling of the process. Walsh said he would take the matter under advisement and start working on a ruling after his vacation planned for next week.

The hearing Friday continued one the judge began a month earlier, when he told the activists' attorneys an outside investigation might be unnecessary since the U.S. Justice Department declined to charge the white officer who shot and killed the unarmed, black 18-year-old. The county grand jury already had chosen not to prosecute officer Darren Wilson, who later resigned.

Lawyers for the activists argued that the grand jury decision in November was inappropriately influenced by McCulloch's conduct.

"Mr. McCulloch put his thumb on the scale," attorney Maggie Ellinger-Locke told the judge Friday. "I'm arguing the process was skewed from the beginning."

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. The federal agency did, however, 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.

He then told Ellinger-Locke: "You're just nitpicking at certain things that were done or not done."

Ellinger-Locke said the federal findings are irrelevant to the push for a special prosecutor. She insisted the scope of the U.S. government's investigation was merely to determine whether Wilson violated Brown's civil rights.

"These proceedings are about whether the grand jury process was conducted appropriately," she said.

Walsh retorted that the Justice Department did an independent probe that included FBI interviews of the same witnesses who offered grand jury testimony, and roughly a dozen of them corroborated Wilson's account.

Ellinger-Locke disagreed, saying, "I think he would have been indicted had this process been aboveboard."

The grand jury decision touched off angry, sometimes violent, protests in Ferguson similar to the unrest that occurred in the St. Louis suburb immediately after Brown's death in August. 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.