U.S. Attorney General Eric Holder sought Wednesday to reassure the people of Ferguson about the investigation into Michael Brown's death and said he understands why many black Americans do not trust police, recalling how he was repeatedly stopped by officers who seemed to target him because of his race.

Holder made the remarks during a visit to the St. Louis suburb that has been wracked by more than a week of unrest since the black 18-year-old was shot and killed by a white officer, Darren Wilson.

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Attorney General Eric Holder shakes hands with Bri Ehsan, 25, right, following his meeting with students at St. Louis Community College Florissant Valley in Ferguson, Mo., on Wednesday. (Pablo Martinez Monsivais/The Associated Press)

The attorney general remembered how he was stopped twice on the New Jersey Turnpike and accused of speeding. Police searched his car, going through the trunk and looking under the seats.

"I remember how humiliating that was and how angry I was and the impact it had on me," Holder said during a private meeting with about 50 community leaders at the Florissant campus of St. Louis Community College.

Holder also met with federal officials investigating Michael Brown's Aug. 9 death and with Brown's parents.

Diminished numbers

He also met briefly with Missouri State Highway Patrol Capt. Ron Johnson, who has been in charge of security in the community for nearly a week since relieving Ferguson police. The National Guard has also been called in to help keep the peace.

Asked whether he had confidence in the local investigation of the police officer, Johnson said Holder's presence "is a guarantee on that."

Some protesters returned to the streets Wednesday evening but in diminishing numbers. They marched around a single block as a thunderstorm filled the sky with lighting and dumped rain. Police still stood guard, but many wore regular uniforms rather than riot gear.

Grand jury hearing evidence

In nearby Clayton, a grand jury began hearing evidence to determine whether Wilson should be charged in Brown's death.

A spokesman for St. Louis County Prosecutor Bob McCulloch said there was no timeline for the process, but it could take weeks.

At the college, Holder told his audience that the most experienced agents and prosecutors would be assigned to the Ferguson investigation.

Outside the St. Louis County Justice Center in Clayton, where the grand jury convened, two dozen protesters gathered in a circle for a prayer, chanted and held signs urging McCulloch to step aside.

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Protesters gather outside the Buzz Westfall Justice Center on Wednesday in Clayton, Mo., where a grand jury begin hearing evidence regarding the police shooting of Michael Brown. (Jeff Roberson/The Associated Press)

McCulloch's deep family connections to police have been cited by some black leaders who question his ability to be impartial in the case. McCulloch's father, mother, brother, uncle and cousin all worked for the St. Louis Police Department, and his father was killed while responding to a call involving a black suspect.

The prosecutor, who is white, has insisted his background will have no bearing on the handling of the Brown case, which has touched off days of nighttime protests during which authorities used tear gas and rubber bullets to clear the streets.

Police release video in separate fatal shooting

Meanwhile, St. Louis Police on Wednesday released a cellphone video and 911 calls in connection with the police shooting death of Kajieme Powell.

The 25-year-old man was approached by police just after noon on Tuesday, about six kilometres away from the site of the Brown shooting. Police allege Powell had stolen items from a convenience store and was carrying a knife.

Police are heard warning him to drop the knife, while it appears at one point Powell shouts: "Shoot me, shoot me now."

The cellphone video, shot from a distance, depicts Powell falling after several shots are fired. It is unclear given the distance from the events how close Powell was to the two officers.

St. Louis Police said it was releasing the graphic video and 911 calls to be transparent and build public trust.

St. Louis Mayor Francis Slay had said Tuesday there will be an investigation to determine whether police acted appropriately.

Officer suspended for pointing assault rifle

On Wednesday, police said an officer had been suspended for pointing a semi-automatic assault rifle at demonstrators in Ferguson, then cursing and threatening to kill one of them. A protester captured the exchange on video Tuesday and posted it to YouTube and other websites.

Meanwhile, Brown's funeral arrangements were set. The Austin A. Layne Mortuary, which is handling arrangements, said the funeral will be at 10 a.m. Monday at Friendly Temple Missionary Baptist Church in St. Louis. Brown's uncle, the Rev. Charles Ewing, will deliver the eulogy, and the Rev. Al Sharpton will also speak.

Brown will be buried at St. Peter's Cemetery in St. Louis County.

Holder said the Obama administration has been trying to achieve change through the Justice Department's civil rights division.

"The same kid who got stopped on the New Jersey freeway is now the attorney general of the United States," he added. "This country is capable of change. But change doesn't happen by itself."

With files from CBC News