(CNN) More than a week after Freddie Gray was arrested in Baltimore, and a day since he died, authorities are still scrambling to find out exactly what happened and why.

"I'll tell you what I do know, and right now there's still a lot of questions I don't know. I know that when Mr. Gray was placed inside that van, he was able to talk. He was upset. And when Mr. Gray was taken out of that van, he could not talk, and he could not breathe," Baltimore Deputy Police Commissioner Jerry Rodriguez told reporters Monday.

He spoke the same day an autopsy was done on the body of Gray, which showed that he died from a severe injury to his spinal cord. "What we don't know, and what we need to get to, is how that injury occurred," Rodriguez said.

The Baltimore Police Department is investigating the death, and has asked for calm as the process unfolds. But many in the community, including the city's mayor, are angry.

"This is a very, very tense time for Baltimore City, and I understand the community's frustration. I understand it because I'm frustrated. I'm angry that we are here again -- that we have had to tell another mother that their child is dead," Mayor Stephanie Rawlings-Blake told reporters. "I'm frustrated not only that we're here, but we don't have all of the answers."

Officers suspended

Police Commissioner Anthony Batts said that police plan to conclude their investigation by Friday, May 1. From there, the case will go to the state's attorney's office, which will decide whether or not to file.

Gray was arrested a week ago Sunday. He "gave up without the use of force," according to Rodriguez.

An officer apparently took his Taser out, and was prepared to use it on Gray, but he never deployed it.

"None of the officers describe using any force against Mr. Gray," said the deputy police commissioner.

A total of six officers were involved in the arrest, and all six have been suspended.

Weapon charge

According to documents obtained Monday, Gray was arrested on a weapon charge.

While the court documents allege that Baltimore Police Department Officer Garrett Miller arrested Gray after finding a switchblade in his pocket, the Gray family attorney called the allegation a "sideshow." Gray was carrying a "pocket knife of legal size," attorney William Murphy told CNN.

Police never saw the knife and chased Gray only after he took off running, the attorney said.

That seems substantiated by the court documents, which said Gray "fled unprovoked upon noticing police presence."

"The officer noticed a knife clipped to the inside of his front right pants pocket. The defendant was arrested without force or incident," the documents say. "The knife was recovered by this officer and found to be a spring assisted, one-hand-operated knife."

Maryland law makes it illegal to "wear or carry a dangerous weapon of any kind concealed on or about the person," including switchblades.

But Baltimore's mayor stressed that simply having a knife is not necessarily a crime.

"It is not necessarily probable cause to chase someone. So, we still have questions," said Rawlings-Blake.

Timeline sparks questions

Gray's death Sunday, following a week of hospitalization, has spurred outrage. At a Monday morning protest outside the Baltimore Police Department, demonstrators co-opted slogans from other high-profile police shootings. They chanted -- "Hands up! Don't shoot!" and "I can't breathe!" -- and carried signs saying, "Stop police terror" and "Black lives matter."

Sharon Black, one of the rally's organizers, said police misconduct is routine in Baltimore, and described Gray's death as the "straw that broke the camel's back."

"The police act in an unrestrained and abusive way," she said.

Sharon Black who helped put rally together talks about the relationship btwn pd and community #cnn #FreddieGray pic.twitter.com/cOjj7AqSf5 — Carolyn Sung (@CarolynSungCNN) April 20, 2015

Gray was in perfect health until police chased and tackled him in Baltimore over a week ago, his lawyer said. Less than an hour later, he was on his way to a trauma clinic with a spinal injury, where he fell into a coma.

Two witnesses hit record on their cell phones during what looked to be the 25-year-old's arrest. Police told CNN affiliate WJZ that they also have surveillance video of him.

But there appears to be a gap of some minutes left to account for. Police, according to their own timeline, spotted Gray, gave chase, caught him, cuffed him and requested a paddy wagon in fewer than 4 minutes. The transport van left with Gray about 11 minutes after that, police said, and another 30 minutes passed before "units request paramedics to the Western District to transport the suspect to an area hospital."

Gray died Sunday, a full week after the encounter.

Police encounter

When cell phones began recording, Gray was already on the ground with three officers kneeling over him. And he let out long, painful screams.

Officers had encountered him a minute earlier, police said. They were working an area where drug deals and other crimes are common, Deputy Police Commissioner Rodriguez said.

They thought Gray may have been involved in a crime, but there was no evidence that he committed a crime, Gray family attorney Murphy said, and WJZ reported last week that police had not said what their suspicion was.

"Officers were working in an area that is known for violent crime and drug sales. Officers went to make an encounter with Mr. Gray when he fled from them," Baltimore Police Department spokesman, Capt. Eric Kowalczyk, said Sunday.

Pressed on why police initially stopped Gray, Kowalczyk said the department hadn't released that information because investigators are still conducting interviews.

Painful wailing

When officers approached Gray, he ran. They pursued and caught him quickly, at 8:40 a.m., according to a police timeline.

The officers called for a prisoner transport van. Cell phone video taken from two separate positions showed officers lifting Gray, whose hands were cuffed, up by his shoulders and dragging him to the back of the van.

He legs dangled behind him listlessly as he wailed.

Officers put more restraints on Gray inside the van, police said, while surveillance video recorded him conscious and talking.

The 30 minutes

That was at 8:54 a.m.

At 9:24 a.m., police called an ambulance to pick Gray up at the Western District police station. Murphy wants to know what happened in those 30 minutes in between.

At some point after his arrest, Gray requested medical attention, said Rodriguez, the deputy police commissioner. Gray also asked for an inhaler, Rodriguez said.

"He lapsed into a coma, died, was resuscitated, stayed in a coma and on Monday underwent extensive surgery at Shock Trauma to save his life," Murphy said. "He clung to life for seven days."

Tubes, wires and supports protruded from Gray as he lay in his hospital bed in a photo Murphy passed on to the media.

Officers and Gray investigated

Rawlings-Blake said that she wants to see a thorough inquiry and that the city will release additional details as investigations are completed.

There will be two criminal investigations, said Deputy Commissioner Rodriguez: one to determine if the arresting officers broke the law, and one that pertains to Gray.

Police have not grilled the arresting officers on what happened for legal reasons, Rodriguez said.

"We cannot interview an officer administratively and compel them, if an officer is the subject of the criminal investigation. Every person has the right against self-incrimination, so for us to compel an officer to provide a statement, that could potentially taint the criminal investigation," he said.

Investigators will submit their results to an independent review board, he said. There will also be a separate administrative investigation.

Family declined meeting

Police officials have attempted to speak with Gray's relatives to explain the investigation process, Police Commissioner Batts said.

But they have declined to meet.

"A mother has lost her son," Batts said, extending his condolences to the family.

He hopes that in interactions between police and residents, everyone goes home safely, he said. "All lives matter."

Gray had a long history of run-ins with the law. A search of his name brings up more than 20 cases in the Maryland judiciary going back to 2007. They're mostly drug-related charges, though he was charged with second-degree assault, according to court documents.

He also spent a month in prion in 2013 for drug possession, and he was due in court Friday on another possession charge, Shields said.