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Three children are missing after an SUV went over a cliff Monday along the Northern California coast, killing their parents and three of their siblings.

One of the missing children is Devonte Hart, who captured the hearts of America in November 2014 when a photo went viral of him hugging a police officer during a Ferguson-related rally in Portland.

Devonte's adoptive parents, Jennifer and Sarah Hart, died when a 2003 GMC Yukon drove off a dirt turnout and appear to have intentionally driven off a cliff, plunging about 100 feet. His siblings, 19-year-old Markis, 14-year-old Jeremiah and 14-year-old Abigail were also killed.

The two women were still in the vehicle and their children's bodies were found out of the vehicle.

Police are still looking for 15-year-old Devonte and his other siblings, 16-year-old Hannah and 12-year-old Sierra.

RELATED: Three children missing after parents, 3 siblings die in Calif. crash

Hart, who was 12 years old at the time that the photo was taken, hugged Portland Police Sgt. Bret Barnum during a rally in Portland the day after a grand jury decided not to charge Ferguson, Mo. police officer Darren Wilson in the shooting of 18-year-old Michael Brown.

A photo of the hug, taken by freelance photographer Johnny Nguyen and first published on OregonLive.com, went viral. It reached No. 1 on Reddit and was shared several hundred thousand times on Facebook.

Barnum, released a statement Thursday morning.

"As you can imagine, the tragic news about Devonte and his family deeply saddens me. The short interaction with Devonte in November 2014 was certainly one of those moments in my career which reinforced my love, passion, and duty in providing compassion and service to my community. At this point I am uncomfortable speaking about the Hart family tragedy until the investigation is complete."

At the time the photo was taken, Barnum told The Oregonian he saw Hart standing in the crowd, with tears in his eyes and holding a sign that read, "Free Hugs." He called Hart over and they talked briefly about the protest and other topics, like art, school and life. He then asked Hart for a hug.

VIDEO: Devonte Hart - The Hug Seen Around The World

After the hug went viral, Devonte's adoptive parents shared more about the encounter in a Facebook post.

"I noticed Devonte was struggling. Tears. He wouldn't speak. He was inconsolable. My son has a heart of gold, compassion beyond anything I've ever experienced, yet struggles with living fearlessly when it comes ot the police and people that don't understand the complexity of racism that is prevalent in our society.

"He trembled holding a Free Hugs sign as he bravely stood alone in front of the police barricade. Tears rushing from his eyes and soaking his sweater, he gazed upon them not knowing how they would react. After a while, one of the officers approached him and extended his hand. Their interaction was uncomfortable at first.

"There were generic questions about his favorite subject and what he liked to do in the summer, but the one that mattered hit straight to the heart. He asked Devonte why he was crying. His response about his concerns regarding the level of police brutality towards young black kids was met with an unexpected and seemingly authentic (to Devonte), 'Yes. I know. I'm sorry. I'm sorry.' The officer then asked if he could have one of his hugs."

In May 2015, Jennifer Hart spoke about the reaction to the photo. Not all of the reaction was positive. She said reporters camped outside their home and they received death threats in the mail.

Devonte was one of six children adopted by Jennifer and Sarah Hart. According to Jennifer Hart, Devonte had a challenging start to life, marred by drugs and extreme poverty.

"He inspires me every single day," Hart said in 2014. "He has proven doctors, psychologists and teachers wrong. His future is most definitely not bleak; he is a shining star in this world. His light shines bright on everyone on his path.”

Drone video: Scene of the crash