BALTIMORE

What happened to Freddie Gray?

People across the nation are demanding to know after the 25-year-old black man suffered a fatal spinal cord injury under mysterious circumstances after being arrested by Baltimore police and put into the back of a police van.

Mr. Gray died April 19, a week after police handcuffed him, forced him into the van and transported him to a hospital.

Officers said they apprehended him after he fled on foot after making eye contact with approaching police officers in an area of West Baltimore they said is known for drug dealing and other criminal activities.

Baltimore Police Department officials said they have no evidence that their officers used excessive force. A lawyer for Mr. Gray’s family accuses the department of a cover-up.

As the U.S. Justice Department opened a civil rights inquiry Tuesday into Mr. Gray’s death, police officials announced that six officers involved with Mr. Gray’s arrest were suspended.

They were identified as Lt. Brian Rice, 41, who has been with the department since 1997; Sgt. Alicia White, 30, with the department since 2010; Officer Caesar Goodson, 45, who has been there since 1999; and Officers Garrett Miller, William Porter and Edward Nero, who joined the force in 2012.

Baltimore Mayor Stephanie Rawlings-Blake and Police Commissioner Anthony W. Batts called for calm to allow police to complete their investigation into Mr. Gray’s death. Authorities said they expect to conclude it by Friday, May 1. From there, the case will go to the state’s attorney’s office, which will decide whether any criminal charges will be filed.

“Mr. Gray’s family deserves justice, and our community deserves an opportunity to heal, to get better and to make sure that something like this doesn’t happen again,” Ms. Rawlings-Blake said.

She said she intends to find out why police stopped Mr. Gray in the first place.

Hundreds of demonstrators have taken to the streets since Monday, demanding answers, justice and a stop to the police killings. The protests have been peaceful and protesters show no signs of letting up.

Chanting “Black Lives Matter” and “Justice for Freddie,” demonstrators marched Tuesday evening on the block where Mr. Gray was arrested. The Rev. Jamal Bryant of the Empowerment Temple in Baltimore asked for a moment of silence. Mr. Gray’s relatives, including his mother, Gloria Darden — her head shrouded in the hood of a sweatshirt — paused quietly.

She later collapsed in tears and was led away by family and friends.

“This is a grieving family that deserves answers,” Rev. Bryant said. “It’s a sign of strength, of one unity and one commitment that we will not rest until we get justice for Freddie Gray.

“The world is watching, and the world needs to see that black Baltimore is unified,” he added.

More demonstrators assembled in front of the Western District police station Wednesday afternoon and also planned to rally Thursday in front of City Hall.

Last Saturday, demonstrators from a separate group called “March2Justice” rallied in Baltimore to support those calling for justice for Mr. Gray.

They made the special stop during a more than 200-mile trek that began April 13 in New York City and concluded April 21 in Washington to demonstrate the increasing incidents of police brutality against African-American males — from Eric Garner in New York City to Walter Scott in Charleston, S.C., to Rumain Brisbon in Phoenix.

Actor and human rights activist Danny Glover backed their efforts.

“The time is now for action-based initiatives to supersede wishful thinking, ” he said in a statement.

Police said they found a knife clipped to the inside of Mr. Gray’s front pants pocket when he was apprehended on the morning of April 12, authorities said.

Officers requested a van to take him to the police station. A citizen videotaped a portion of the encounter on a cell phone, which showed police dragging Mr. Gray into the van. He was handcuffed and hollering about pain.

While it’s unclear what happened in the van, the Baltimore Sun reported that Mr. Gray, who suffered from asthma, asked for an inhaler.

At some point during his roughly 30-minute ride, the van was stopped and Mr. Gray’s legs were shackled when an officer felt he was becoming “irate,” police said.

Mr. Gray lapsed into a coma, was resuscitated, had surgery on April 13 and then “clung to life for seven days” before dying April 19 in the hospital, said William H. Murphy Jr., the family’s attorney.

His relatives said he suffered fractured vertebrae and a crushed larynx. Mr. Murphy said Mr. Gray’s spine had been nearly severed at the neck while he was in custody.

According to arrest papers filed by Officer Miller, Mr. Gray was charged with carrying a knife.

“If we stay calm at a time like this, there is something wrong with us,” one man told reporters.