ST. LOUIS A local prosecutor who inherited the long-running case of a Chillicothe man facing a third murder trial in his neighbor's shooting death wants to be removed because of Facebook posts he thinks pose a conflict of interest by linking him to efforts to free the twice-convicted felon.

Livingston County Prosecutor Adam Warren was appointed to the case last week after a northwest Missouri judge barred the state attorney general from again prosecuting Mark Woodworth in Cathy Robertson's 1990 death. The judge said that previous prosecutorial missteps and a Robertson family private investigator's "secret investigation" on behalf of the county tainted evidence used to convict Woodworth.

The Associated Press obtained a written request filed by Warren on Monday in Platte County Circuit Court, citing a "social media position which may cast a prejudgment claim" on his ability to independently review the evidence against Woodworth before deciding whether to again file murder charges. Rhonda Oesch, Cathy Robertson's daughter, said the family met with Warren a day or two after his Jan. 29 appointment to discuss several concerns about his involvement, including online comments made by Woodworth supporters suggesting Warren would not prosecute.

Oesch said she and one of her sisters also hired Warren within the past two years to handle real estate transactions. Like many small-town prosecutors in Missouri, Warren works for the county part time while also keeping a private practice in Chillicothe.

A letter to Warren signed by 12 members of the Robertson family also cites his unsuccessful 2012 campaign for attorney general, in which Warren lost a Republican primary election to Ed Martin, who in turn was defeated by incumbent Chris Koster, a Democrat.

"Your (past) campaign for attorney general makes us nervous that there remains an incentive to embarrass the Attorney General's Office by not litigating the case," the letter reads.

Warren said he was invited to participate in a pro-Woodworth Facebook group but never joined the closed group. He said that while the Robertsons' other concerns "did not amount to anything," he asked to be removed "out of an abundance of caution" and after consulting with ethics experts at The Missouri Bar, which licenses the state's lawyers.

"I've got to be very careful," he said. "I can already tell that whatever happens, it's going to be a point of contention."

More than two decades ago, the family's previous concerns with the reluctance of a Warren predecessor to file charges against Woodworth led to the appointment of the Missouri Attorney General's Office.

Woodworth, 39, has been free on bail for nearly one year after the Missouri Supreme Court overturned his second conviction in Robertson's death, saying prosecutors failed to share evidence that could have helped his defense.

In a court motion opposing Warren's request to appoint a special prosecutor, Woodworth's attorneys cite the earlier efforts to remove a local prosecutor as part of the victim's family's "long history of inappropriately attempting to influence the case."