ST. LOUIS - Supporters of criminal justice reform are questioning a move by assistant prosecutors in St. Louis County to join a police union, as well as the timing of the vote just weeks before a change-minded prosecutor takes office.

Assistant prosecutors and investigators voted Monday to join the St. Louis Police Officers Association, a union known for its fierce and unyielding loyalty to officers.

The vote came just a couple of weeks before the first-ever African-American person elected as St. Louis County prosecutor, Wesley Bell, replaces Bob McCulloch, who gained a reputation as a tough law-and-order prosecutor in nearly three decades in office. Bell easily defeated McCulloch in the August Democratic primary and ran unopposed in November. He takes office next month.

Bell spent three years as a city councilman in Ferguson, the St. Louis County town where a white officer fatally shot 18-year-old Michael Brown, who was black and unarmed, in August 2014, setting off months of often-violent protests.

Bell ran as a reformist. He opposes the death penalty, wants to direct more people with minor drug crimes to treatment instead of jail, and wants to eliminate cash bail for people accused of low-level crimes. He has said he will stand behind officers as long as they act appropriately, but those who step out of line should be held accountable.

John Chasnoff, an activist who has pushed for more police accountability in the St. Louis area, said the timing of the union vote is not coincidental.

"People have to put two and two together here and see that we have a new person of colour coming into that office who's been elected on a platform of reform," Chasnoff said. "For the office to react that way sends a clear message that prosecutors are rejecting the community's clear mandate that came out of the election."

Jeff Roorda, business manager for the police union, declined comment. McCulloch's office did not return a message seeking comment.

Bell, through a spokeswoman, declined an interview request. He said in a statement that he supports the rights of prosecutors to organize.

"The choice of the police union raises some questions, though we will work in good faith to minimize any cost to taxpayers or conflicts with the police union that this could present," Bell said. He added that he remains "committed to fulfilling the promises for change that St. Louis County voters resoundingly demanded with my election."

Webster University criminologist Remy Cross called the union vote "a shot across the bow" aimed at showing Bell that his staff supports McCulloch's hardline approach to dealing with crime.

Cross characterized the message of the vote this way: "You can come in and you can say you're going to shake things up, you can say you're going to change stuff, but maybe not."

Prosecutors' membership in a union is rare but not unheard of, Cross said. Across Missouri, assistant prosecutors in Jackson County, which includes Kansas City, are members of a firefighters union.

The St. Louis Police Officers Association represents St. Louis city officers. St. Louis County officers are part of a separate union, so the county's police and prosecutors won't be members of the same union.

Still, Rashad Robinson, president of the civil rights group Color of Change, said the prosecutors' membership in any police union presents the risk of conflict of interest — especially in the St. Louis area that has been the subject of intense scrutiny since Michael Brown's death over how police interact with black residents.

"So to align themselves with a police union is deeply troubling because they are supposed to be independent," Robinson said.

News from © The Associated Press, 2018