(Refiles to add dropped word "a" in first paragraph)
By Carey Gillam
FERGUSON, Mo. Aug 14 (Reuters) - Bob McCulloch is in a difficult situation.
As St. Louis County prosecuting attorney, McCulloch is responsible for deciding whether to pursue criminal charges against the police officer who fatally shot 18-year-old Mike Brown on Saturday outside a low-income apartment complex in Ferguson, Missouri.
The shooting of the unarmed black teenager sparked days of rioting and protests in Ferguson and surrounding communities and some residents say the mostly white ranks of local and county law enforcement officials are not objectively investigating the case.
McCulloch, 63, has held the top county prosecutor's job for 23 years and has promised an impartial investigation of Brown's death. But protesters say McCulloch, whose police officer father was killed in the line of duty when McCulloch was a child, should be removed from the case.
"I don't trust Bob McCulloch," community activist Anthony Shahid said as he helped lead a march by roughly 100 people at the St. Louis County Justice Center this week. "His father was killed by a black man."
A meeting arranged between a group of the protesters and McCulloch was canceled Tuesday after the two sides could not agree to the terms, said Edward Magee, a spokesman for McCulloch.
The prosecutor declined to be interviewed but Magee said the accusations of bias against McCulloch are unfounded.
"He has been involved in these type of cases before and has always been fair and open and will continue to be," Magee said.
Last month, McCulloch's office filed charges against a St. Louis County police officer for assaulting a 24-year-old man with a baton. The officer was black but St. Louis County has brought criminal charges against several police officers, both black and white, in the past, Magee said.
McCulloch is not known to shy away from controversy. In 2001 he was criticized heavily but stood behind comments that two men fatally shot by a police officer and federal drug agent were "bums" who were killed during an attempted arrest.
As a child, McCulloch wanted to be a police officer like his father but decided to pursue a career as a prosecutor after losing his right leg to cancer in high school, according to a profile in the St. Louis Post Dispatch.
McCulloch is well respected by colleagues across the state, said Matt Selby, president of the Missouri Association of Prosecuting Attorneys, and is frequently called on to help in difficult cases.
"Personally, he is basically above reproach," Selby said. "He has a vast amount of experience. But you can't be in the jobs we are in and not have people complaining."
McCullough is up for re-election this year and on Aug. 5 handily won his first primary challenge since 1998.
The married father of four grew up in St. Louis and earned his undergraduate and law degree from St. Louis University, according to media profiles. He was a clerk for the Missouri Court of Appeals before becoming an assistant prosecuting attorney in St. Louis County in 1978.
DEMANDING A NAME
Protesters have demanded the name and other information about the officer involved in Brown's shooting as well as more details about how many shots were fired and why the officer used deadly force. But McCulloch's office and local and county police have so far refused to identify the officer, other than to say he had served for six years on the Ferguson police force.
One witness, Dorian Johnson, who was walking with Brown at the time, has said in media interviews that Brown put his hands in the air and was not struggling with the officer. He said the officer fired multiple times into Brown's head and chest. The police officer said Brown was going for his gun when he was shot, according to authorities.
St. Louis County police detectives are preparing a detailed report on the matter, which they plan to deliver to McCulloch in roughly two weeks, officials said. The prosecutor will then evaluate if criminal charges are appropriate.
Officials say the protests and lack of trust in authorities is delaying the investigation and in a news conference Wednesday McCulloch pleaded for more witnesses to come forward. "We are in still the information gathering part of the investigation," he said.
"One thing that I have pledged is that we will do a full, fair, complete and impartial investigation into this. Nothing will be left untouched. But if we can't get that information in it doesn't do anybody any good." (Reporting by Carey Gillam; Editing by Bill Trott)