Story highlights Michael Brown's stepfather says he's sorry for yelling "Burn this bitch down" last week

Police are investigating whether Louis Head intended to incite riot, police chief says

Don't expect Head to be prosecuted because it's tough to prove, law enforcement says

"We just wish he would just shut up," law enforcement official says of Ferguson police chief

Michael Brown's stepfather says he's sorry for his emotional outburst to demonstrators after learning Officer Darren Wilson wouldn't be indicted in the teen's death. But he says he's unfairly taking heat for the rioting that followed.

Despite Ferguson Police Chief Tom Jackson's assertion that police are investigating whether Louis Head intended to incite a riot with his words, law enforcement sources told CNN that Head is unlikely to be prosecuted.

Head said Wednesday that "emotions got the best of me" on the night of November 24 in Ferguson, Missouri, when he yelled "Burn this motherf---er down!" and "Burn this bitch down!"

"I was so angry and full of raw emotions, as so many others were, and granted, I screamed out words that I shouldn't have screamed in the heat of the moment," he said in a statement obtained exclusively by CNN's Don Lemon. "It was wrong, and I humbly apologize to all of those who read my pain and anger as a true desire for what I want for our community.

"But to place blame solely on me for the conditions of our community, and country, after the grand jury decision, goes way too far and is as wrong as the decision itself. To declare a state of emergency and send a message of war, and not peace, before a grand jury decision was announced is also wrong.

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"In the end, I've lived in this community for a long time. The last thing I truly wanted was to see it go up in flames. In spite of my frustration, it really hurt to see that."

No charges likely

Don't expect any charges to come from the Ferguson and St. Louis County Police investigation into Head's comments, local law enforcement officials tell CNN.

The officials say the investigation isn't likely to go anywhere, in part because it would face a high bar to prove that Head's words actually caused any rioters to act.

One law enforcement official was frustrated by Jackson's comments, which officials view as inflammatory at a time when they're trying to calm the situation.

"We just wish he would just shut up," the law enforcement official said.

Even if the investigation into Head's comments doesn't result in charges, the police investigation could still cause problems for him. Federal court records indicate he is on probation for a previous drug charge.

CNN reached out to his probation officer, but there was no response to a request for comment.

'He just spoke out of anger'

Brown's mother, Lesley McSpadden, was standing next to Head, her husband, when he made the comments. She herself told the crowd that night that she'd never experienced anything like this, and offered some context in a CNN interview last week.

After hearing the grand jury's decision, McSpadden said she felt like she'd been shot herself and her "emotions were raging." Head was angry, too, she said.

"He just spoke out of anger. It's one thing to speak, and it's a different thing to act. He did not act. He just spoke out of anger," she said. "When you're that hurt and the system has did you this wrong, you may say some things as well. We've all spoke out of anger before."

Asked if her husband could be responsible for the fires and rioting, she replied, "That's impossible. ...These things have been going on since August 9, when it first happened."

'Cause and effect ... hard to prove'

CNN law enforcement analyst Tom Fuentes told CNN on Tuesday that he thought a prosecution was unlikely.

"I think they'll have a hard time proving that somebody that heard him in the midst of all that noise actually went over and did an arson or committed an act of starting a fire. I think most of the people you see in the crowd are not watching CNN. They're not watching media reporting of him saying that," he said.

Also, Fuentes said, it's likely many people who had gathered in Ferguson as the grand jury's decision was announced were already determined to act.

"I think the cause and effect of his words will be hard to prove," Fuentes said.

Protests nationwide

Brown's August shooting death -- and last week's grand jury decision not to indict the officer who killed him -- have sparked numerous protests in Ferguson and across the country.

Demonstrations heated up again on Wednesday after a grand jury in New York decided not to indict a police officer in the choking death of Eric Garner, an unarmed black man suspected of selling cigarettes illegally.

Four members of the Denver Police Department's bicycle unit were injured after they were struck by a car while doing crowd control as a large group of high school students protested the Ferguson grand jury's decision, CNN affiliate KUSA reported . One of the officers is in critical condition undergoing surgery, police said.

This week Attorney General Eric Holder visited Atlanta in what he said would be a series of nationwide conversations after the upheaval in Ferguson.

"This presents this nation with, I think, a unique opportunity," Holder said. "And I think it's incumbent on all of us to seize this opportunity to deal with issues that for too long have been ignored."

Holder will be traveling to Cleveland on Thursday, the Justice Department said, followed by trips to Memphis, Tennessee, Chicago, Philadelphia and Oakland, California.