McClain was walking home from a convenience store in Aurora, Colorado, on the night of Aug. 24, 2019, when the encounter happened with police, the petition stated. The Aurora Police Department said the incident began when officers received a "suspicious person" call about somebody "wearing a ski mask and waving his arms at the caller."

"Officers arrived in the area and contacted a male wearing a ski mask," APD said in a press release. "The male would not stop walking down the street from the officer. The male resisted contact, a struggle ensued, and he was taken into custody."

According to the police department, McClain had to get medical attention from first responders because "the level of physical force applied while restraining the subject" agitated McClain's "mental state."

The Aurora man was taken to the hospital and was pronounced dead on Aug. 27, the petition stated. According to Denver 7ABC, the coroner didn't determine if McClain's death was an accident, if it was because of natural causes, or if it was caused by police using a chokehold on the young man.

"The decedent was violently struggling with officers who were attempting to restrain him," the report stated. "Most likely the decedent's physical exertion contributed to death. It is unclear if the officer's action contributed as well."

The family's attorney, Mari Newman, said McClain wasn't a threat to anybody and that police used excessive force. 

"Whatever the report says, it's clear that if the police had not attacked Elijah McClain, he would be alive today," Newman told 7ABC. 

The attorney said there is more reason for suspicion because police said the body cameras of the three officers fell off.

"It makes it awfully easy for them to say whatever they want, but what we know is that they attacked him for no reason whatsoever," Newman said. "It was excessive force and it led to his death."

Newman said she has seen video footage that hasn't been released by the department. 

"What the video shows is that the officers, all three, went hands-on with him immediately, threw him against a wall and tackled him to the ground," the attorney said. "He was restrained and they continued to use force against him, pinned him to the ground, and as he was vomiting, they said don't move or we're going to call in a dog to bite you."

Newman also said there is proof of "tampering with evidence" in a video that shows one of the officers lifting up the body camera of one of his colleagues and the other officer saying "hey, get that away, move that out of the way dude." 

Denver art teacher Matty Miller created a portrait to show McClain’s hobbies. The picture included musical instruments, a cat, plants and specialized running shoes, according to the Sentinel Colorado.

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#JusticeforElijahMcClain This gentle young man was killed by Aurora Police in Colorado less than a year ago. The officers have not been charged for taking his life. Elijah was a 23 year old massage therapist. He taught himself to play violin and guitar. On his lunch breaks from work he would sometimes bring his guitar and play music for the animals in the pet shop. Elijah loved running. He ran in barefoot running shoes because he believed they are more natural for humans to wear. He was anemic and wore a runners mask to stay warm. Content warning for violent description. On the night he was killed, he walked to the store wearing his running mask to buy iced tea for his cousins. Someone called the police about “suspicious behavior.” On the audio footage released by Aurora PD you can hear Elijah crying out, “Let go of me. I’m an introvert. Please respect the boundaries that I am speaking….I can’t breathe.” Elijah was 140 lbs. Even when he was being brutally attacked he spoke with integrity. While 3 Aurora Police Dept officers violently restrained him they called Aurora Fire Dept, who injected him with ketamine. He went into cardiac arrest and his family was advised to take him off life support 6 days later. Please share his story. Demand justice for Elijah— email Aurora representative, sign the petition demanding justice, donate to the McClain family. @justiceforelijahmcclain https://linktr.ee/Justiceforelijahmcclain Support his family’s GoFundMe page here: https://www.gofundme.com/f/elijah-mcclain #blacklivesmatter #sayhisname #justiceforelijah #elijahmcclain #saytheirnames5280 #blm5280

A post shared by Matty Miller Studio (@mattymillerstudio) on Jun 6, 2020 at 9:47pm PDT

“I started researching his story, and it was just heartbreaking and it put me in a state of grief learning about who he was as a person,” Miller told the newspaper. “He felt like somebody I would have been friends with, or had as one of my students. I was just upset and outraged and sad.” 

McClain’s mother, Sheneen McClain, has created a memorial to keep her son's memory alive, according to CBS4.

"This is my son Elijah J. McClain and I am his mother Sheneen McClain aka EagleEyezReadings," Sheneen wrote on a GoFundMe fundraiser for her son. "Elijah was killed by 3 Aurora Colorado police officers because he was a young accomplished black man!" 

Now, the family is determined to find justice. 

“We need to flood the Senate or whoever we need to, to get these bills passed, so that equality is real, and it’s not just an illusion," Sheneen told CBS4. "It has to be real for everybody. It can’t just be just something that’s made up. No more fiction. No more fiction.”

According to The Denver Post, McClain tried to plead with the officers during the encounter.  

“I am going home. Leave me alone,” McClain said, according to the newspaper. “Let me go. No, let me go. I am an introvert. Please respect my boundaries that I am speaking.”

Following the death of George Floyd, more cases like that of McClain have received attention, as Blavity previously reported. One of the cases focuses on Javier Ambler, a 40-year-old man who was tased four times by police in Austin, Texas, as he said "I have congestive heart failure. I can’t breathe."

Advocates have also turned their attention to Darrien Hunt, who was killed by police in 2014 while cosplaying with friends in Saratoga Springs, Utah. The other cases brought to light in recent weeks also involve Black men and women who died suspiciously and whose cases remain unsolved. That's the case for Kenneka Jenkins, a 19-year-old Chicago teen who was found dead in a hotel freezer in 2017 after attending a party with friends. 

You can sign the petition demanding justice for McClain here and/or donate to his mother's GoFundMe.