By Dakin Andone, CNN

(CNN) -- On the night of August 24, 2019, Elijah McClain was walking home from a convenience store with an iced tea when he was confronted by three Aurora, Colorado, police officers.

By the end of the night, the 23-year-old Black man was lying in a hospital bed. Three days later, he was pronounced brain dead and taken off life support, according to a lawsuit filed by his family earlier this month.

McClain's death attracted renewed attention this summer after the police killings of George Floyd in Minneapolis and Breonna Taylor in Louisville, Kentucky. As protests grew nationwide, demonstrations in the Denver suburb emphasized McClain and his family's monthslong search for justice.

It's been a year since police approached McClain, whose family has described him as an energetic and happy person who loved animals and played the violin and guitar.

"It feels like it's been a decade some days," Candice Bailey, a family friend, told CNN affiliate KUSA on behalf of the family.

Here's what you should know about Elijah McClain, his death and where the case stands.

How McClain died

McClain was stopped last August by three officers after a 911 caller reported a suspicious person wearing a ski mask walking along Billings Street in Aurora, according to a police news release. That report says that McClain "resisted contact" with officers before a struggle ensued.

"I'm an introvert," McClain is heard saying in police bodycam footage after officers confront him. "Please respect the boundaries that I am speaking."

"Relax," an officer says at one point, "or I'm going to have to change this situation."

Before an officer wrestles him to the ground, McClain is heard telling the officers he was trying to stop his music so that he could listen to them.

During the struggle, one officer is heard saying, "He just grabbed your gun, dude." One officer tells McClain that he will "bring my dog out and he's going to bite you" if McClain keeps "messing around."

A letter from the Adams County District Attorney said an officer placed McClain in a carotid hold, which restricts blood flow to the brain. McClain briefly lost consciousness, the letter said, but continued struggling after officers released the hold.

The DA's letter said paramedics arrived and administered ketamine, a powerful anesthetic. McClain was taken to a hospital but had a heart attack on the way. He was declared brain dead three days later, on August 27, the letter says.

The autopsy conducted by the county coroner did not determine the cause of death but noted "intense physical exertion and a narrow left coronary artery" were contributing factors.

The report noted McClain's history of asthma and the carotid hold, though the autopsy did not determine whether it contributed to McClain's death. The concentration of ketamine in his system was at a "therapeutic level," the report said.

Ultimately, McClain's death could have been an accident, the result of natural causes or a homicide, the autopsy concluded.

The McClain's family attorney, Mari Newman, called the autopsy "very strange." She has said it "ignores the most obvious factor, which is a perfectly healthy young man is walking home from the drug store with a bottle of iced tea in a bag and he ends up dead."

What happened to the officers

Three officers involved were initially placed on administrative leave, but they were later reinstated when prosecutors declined to file criminal charges.

In a November 2019 letter to Aurora's then-police chief, District Attorney Dave Young wrote that his office did not find enough evidence to prove the officers violated Colorado law or that their use of force was unjustified. A police review board said in February that the use of force, including the carotid hold, "was within policy and consistent with training."

Young has stood by his decision not to charge the officers, but has said McClain's death was "tragic and unnecessary" and previously told CNN he does not condone the officers' actions.

"In fact, I disagree with what they did the night of August 24, 2019," he told CNN's Chris Cuomo in June. But he pointed to the autopsy, saying, "I cannot take a case to the jury where I don't know what the cause of death is on a homicide case."

But amid the recent reckoning over race and police brutality, some felt McClain's death deserved a second look, and by June more than two million people had signed an online petition calling for a new investigation.

In late June, Colorado Gov. Jared Polis tapped Colorado Attorney General Phil Weiser to conduct an independent investigation into McClain's death and bring criminal charges if warranted.

"Elijah McClain should be alive today, and we owe it to his family to take this step and elevate the pursuit of justice in his name to a statewide concern," Polis said in a statement at the time.

This month, Weiser confirmed he was conducting a separate investigation into the police department and whether its "patterns and practices" are unconstitutional. Additionally, the city of Aurora has commissioned its own investigation of the police department, hiring an outside consultant to conduct a "comprehensive review."

McClain was 'a beautiful soul,' family says

McClain's family spent months calling for police reforms and an investigation into the circumstances that led to his death.

"Last year, we stood on the municipal center steps demanding an investigation, and what did we hear then? Crickets," family attorney Mari Newman previously said.

"Why did it take almost a year, international media attention, millions of people signing a petition, for a responsible adult to finally step up and do what should have happened right from the outset?" she asked.

McClain's family filed a federal civil rights lawsuit this month against Aurora, members of the police department and Aurora Fire Rescue. It alleged that McClain's death was "part of a larger, custom, policy, and practice of racism and brutality."

The lawsuit listed nine claims for relief, including excessive force; denial of equal protection; failure to ensure basic safety and provide adequate medical care and treatment; substantive due process -- deprivation of liberty -- forcible administration of medication; battery causing wrongful death; and negligence causing wrongful death.

In a statement, the city of Aurora said it recognized the "tragic nature of the death of Elijah McClain."

"However, the city disagrees with the broad characterizations expressed in the lawsuit, including some that are completely unrelated to the facts of this case," the statement said. "The city continues to take a critical look at our organization and works to put in place reforms that our community wants and deserves."

The city declined further comment, citing ongoing litigation.

In the lawsuit, McClain's loved ones remembered him as a "beautiful soul."

"Elijah's family and community remember him for his outsized kindness and grace, his desire to help and heal, and his thoughtful, spiritual approach to life," it said. McClain would often play violin for animals up for adoption at a local shelter, hoping it would help ease their loneliness, the lawsuit said.

"We have focused so much on what happened to Elijah that we are not focusing on the human being that Elijah was," Candice Bailey, who spoke on behalf of the family, told CNN affiliate KUSA.

McClain's mother told CNN affiliate KCNC that her son, a massage therapist, "wanted to heal" others. "He was able to accept love and give love in varying forms," Sheneen McClain said.

The reforms made since his death

Colorado officials have started implementing some policy changes since McClain's death last August.

Gov. Polis signed a new police accountability law on June 19 called the Enhance Law Enforcement Integrity Act, which bans the use of chokeholds and carotid holds by police.

It also mandates the use of body-worn cameras by police, bars the use of deadly force against those suspected of minor or non-violent offenses, requires officers to intervene if they witness another officer using excessive physical force and establishes new data reporting requirements on the use of force, among other reforms.

"This legislation specifically contains landmark, evidence-based reforms that not only protect civil rights but will help restore trust between law enforcement and the communities that they serve," Polis said.

Aurora Police Chief Vanessa Wilson also banned the use of carotid holds in her department, along with other requirements aimed at de-escalating confrontations with residents.

Meanwhile, state health officials announced a review of the use of ketamine in the McClain case. The state health department said Saturday it would also examine the wider use of ketamine in EMS settings.

But activists still want to see criminal charges brought against a number of individuals, including the officers and EMTs present at the scene of McClain's death, Bailey told KUSA.

"We need some kind of healing within our community," she said, "and what better place to start than with Elijah McClain."