'This has to stop': 31 arrested after fresh confrontation in Ferguson (PHOTO GALLERY)

Ferguson, Mo. (CNN) -- More violence. More tear gas. No answers.

Stun grenades and tear gas canisters arced through the night sky and into crowds of protesters overnight in Ferguson, Missouri, after police said they had been targeted with rocks, Molotov cocktails and gunfire amid continuing demonstrations over the death of Michael Brown.

Two people were shot -- not by police, authorities said. Four officers were injured. Police arrested at least 31 people.

Police and protesters blamed outside agitators for the gunplay and violence.

"We don't need these antagonizers out here," said protester Jerrell Bourrage, who earlier grabbed one of the bottle-hurling demonstrators and told him to stop. "We need people who can stand out here to the side and still let your word be known."

The protests are the latest spasm of violence over the shooting of Brown, an unarmed African-American teenager, by white police Officer Darren Wilson on August 9.

As police and protesters search for a way to stop the chaos, Brown's parents appeared on NBC's "Today" to appeal for justice and say there's just one way out of all this.

"Justice," Brown's mother, Lesley McSpadden, told the NBC show. "Justice will bring peace, I believe."


Situation deteriorates

Monday evening began peacefully enough.

For almost two hours, police in riot gear formed a barricade and stood watch as hundreds of protesters marched in a single-file line that stretched so long that different parts chanted different slogans.

"Hands up, don't shoot," some repeated. "No justice, no peace," others said. Still others were singing church hymns.

But the scene quickly deteriorated after a handful of protesters threw rocks, bottles and Molotov cocktails at police. Officers responded by firing stun grenades and tear gas canisters.

Amid the frenzy, gunshots could be heard. Police found two people shot within the protest site, said Missouri State Highway Patrol Capt. Ron Johnson, who is in charge of protest security.

One group of protesters made a barricade with portable toilets and orange cones. Some ripped out street signs, including a symbolic "Do Not Enter" sign.

Armored vehicles rolled down the streets with officers perched atop, their hands steadied on guns. Other officers darted into the protest crowd to make an occasional arrest before retreating.

Johnson said that a building and an unoccupied house were set on fire, and that his officers came under "heavy gunfire."

"We have been criticized for using SWAT trucks during protests. We did not deploy them into crowds until things deteriorated," he said. "Once again, not a single bullet was fired by officers despite coming under heavy attack."

CNN accounts of the protest varied.

On Monday night, CNN's Jake Tapper echoed the frustrations of many in the crowd.

"Absolutely there have been looters, absolutely over the last nine days there has been violence, but there is nothing going on in this street right now that merits this scene out of Bagram. Nothing.

"So if people wonder why the people of Ferguson, Missouri, are so upset, this is part of the reason. What is this? This doesn't make any sense."

However, on Tuesday morning, CNN's Steve Kastenbaum said the police response was among the more restrained in several nights of demonstrations. Police, he said, appeared to be very targeted in responding to "bad actors."

"There are people in this crowd who are here to do more than protest, who come here armed" Kastenbaum said.

To be sure, Johnson displayed weapons seized early Monday.

"This has to stop," he said. "I don't want anybody to get hurt."


Outside provocateurs

Protest leaders tried to calm the situation.

CNN correspondent Ed Lavandera told of watching community religious leaders "get up in the face" of troublemakers in a failed effort to dissuade them from violence.

"Get out of the street! Don't fight!" some protesters bellowed on bullhorns.

Others, like Bourrage, told hold of the agitators and tried to get them to stop.

"I came to keep my brothers safe," Bourrage said. "We have fathers, brothers, mothers and aunties out here."

Malik Shabazz, national president of Black Lawyers for Justice, blamed unspecified outside provocateurs for the trouble.

"We can't allow this movement to be destroyed," he said.

Johnson, during an early morning news conference, urged demonstrators to protest during the daylight hours Tuesday and not after dark.

"Make your voices heard where you can be seen and you're not the cover for violent agitators," he said.

"There is a dangerous dynamic in the night. It allows a small number of agitators to hide in the crowd and then attempt to create chaos."

Parents speak out

Monday's chaos followed a day rich in developments, including details of a private autopsy, an account said to echo what Officer Wilson reportedly says happened and an open letter to the Brown family written by the mother of Trayvon Martin, the Florida teenager killed in a scuffle with neighborhood watch volunteer George Zimmerman.

The autopsy, conducted for the Brown family, showed that Brown had been shot at least six times, including twice in the head. The findings are more than enough to justify Wilson's arrest, Brown family attorney Daryl Parks said Monday.

On "Today," Brown's father, Michael Brown Sr., said the autopsy didn't answer the family's one key question: Why?

"What was the cause of that excessive force?" he said. "Nobody deserved that."

Also on Monday, an account emerged of a telephone call to "The Dana Show" on the Radio America network from a woman claiming to know Wilson's version of events. According to the account -- which a source with detailed knowledge of the investigation said tracks with Wilson's version of events -- Brown rushed Wilson in the moments before the shooting.

Witnesses who have come forward publicly say Brown was standing with his hands in the air when he was shot.

In her open letter, published Monday by Time, Martin's mother, Sybrina Fulton, told the Brown family that good will come of their sons' deaths.

"While we fight injustice, we will also hold ourselves to an appropriate level of intelligent advocacy," she wrote. "If they refuse to hear us, we will make them feel us. Some will mistake that last statement as being negatively provocative. But feeling us means feeling our pain; imagining our plight as parents of slain children."

But first, the Browns must mourn their son, she told CNN on Tuesday.

"He needs to be buried and he needs to be laid to rest," she said.

What's next?

U.S. Attorney General Eric Holder is expected to visit Ferguson on Wednesday to check in on the Justice Department's civil rights investigation into Brown's death.

On Tuesday, a senior White House official told CNN that President Barack Obama isn't currently planning to visit Ferguson. Such a visit would tax law enforcement resources, the official said. He hasn't ruled out a trip sometime later, the official said.

In addition to Holder, who will spend only a day in Ferguson, the government is sending the director of the Justice Department's community policing program for a longer visit to advise law enforcement on how to deal with protesters peacefully, the official said.

A grand jury could begin to hear testimony from witnesses and decide on whether to return an indictment in the case as early as Wednesday.

Meanwhile, fallout continues to affect the community.

The Ferguson-Florissant School District has canceled school for the week, and two nearby districts -- Jennings and Riverview Gardens -- opted to remain closed again Tuesday as well, according to CNN affiliate KMOV.

Some businesses have also been looted or burned, prompting some store owners to arm themselves and stand guard over their shops, according to local media reports.