image source, David Robinson IIimage captionDaniel Robinson (centre), seen here with his mother and grandmother, has been missing for three months as of Thursday

When 22-year-old Gabby Petito didn't return home from her cross-country road trip, her case sparked a firestorm of national media coverage and social media attention. Americans with their own missing relatives have been left wondering why their cases have not received the same interest.

She was found dead in a Wyoming national park. Her partner refused to speak to the police, then vanished. Millions of people followed along on newspaper front pages, cable news shows and social media.

Every new development in the Gabby Petito case has been amplified and analysed by sleuths, professional and amateur.

Amid the suggestions and conspiracy theories, a flood of tips helped lead law enforcement to where Ms Petito lay dead.

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But for hundreds of thousands of other missing Americans, particularly non-white victims, public attention has been scarce.

Researchers call it "missing white woman syndrome" and Michelle N Jeanis, an assistant professor of criminal justice at the University of Louisiana at Lafayette, says it has been in existence for decades.

Ms Jeanis studies the relationship between missing persons and the media. She contends the news media's use of a "cautionary tale framing" around white women as victims is lucrative to the industry and reinforces systemic social biases, especially on social media.

"Young, beautiful, typically middle class, white women are incredibly newsworthy when bad things happen to them," she told the BBC.

In her research, Ms Jeanis found that social media often functions similarly to traditional media in such cases, so "white individuals get far more likes, shares and all forms of [social media] engagement than individuals of colour".

Here are the stories of three people still hoping for answers.

Dawn and Jeff Dayimage source, Lynnette Grey Bullimage captionNine years on, Greg Day still has few answers over the deaths of his two children

Greg Day no longer has "good days", only "OK days". He wishes he could hear his kids laugh again.

In July 2012, his 28-year-old daughter, Dawn, was found floating face-down in the waterways of Fremont County, Wyoming.

Then, almost exactly four years later, his other child, Jeff, also aged 28, was also found dead.

"Greg Day believes that both of his children were murdered," says Lynnette Grey Bull, a confidante of the Day family and founding director of the "Not Our Native Daughters" non-profit.

The organisation is one of many seeking to raise awareness of the crisis of missing and murdered indigenous women in North America. According to the Justice Department, Native women are killed at 10 times the national average.

In Wyoming alone, where Ms Petito went missing, more than 700 Native Americans were reported missing over the last decade. Few have seen their cases resolved or taken seriously.

"I've sat with families that I couldn't give any answers to," says Ms Grey Bull, who sits on the state's task force on missing and murdered indigenous people. "It's a heavy burden to carry these stories and voices."

According to her, Mr Day has sent in tips and penned a personal letter to the Fremont County attorney general this year. Like so many others though, he has received no justice and little help.

"The bottom line for us as Natives is we're always disregarded," Ms Grey Bull tells the BBC.

"The statistic that lies over my head is that I am the most stalked, raped, murdered and sexually assaulted of every ethnicity in this country," she says. "Why are our cases not paid attention to?"

Daniel Robinsonimage source, David Robinson IIimage captionDaniel Robinson was last seen at his geology work site in Buckeye, Arizona, on 23 June

Military veteran David Robinson II has been searching for his youngest son Daniel, 24, for three months.

Daniel was born without a left hand but it did not prevent him from playing everything from football to the trombone. Graduating with honours from the College of Charleston, the amateur rock collector followed his heart into the field of geology.

His father remembers him as mild-mannered but funny, the kind of person that "brings everybody together".

Daniel was last seen leaving his job site in Buckeye, Arizona in his blue-grey Jeep Renegade.

A local rancher found the vehicle in a ravine about two months ago, but the trail has since run cold.

David still has faith his son is alive and he has moved to Arizona, upending his own life, to keep the pressure on investigators.

Buckeye police have sent out off-road vehicles, drones and dogs, but he says their efforts have not been serious. He claims to have conducted his own search operations with over 200 volunteers nonstop for seven weeks.

The family has also set up a GoFundMe and a petition to support their efforts, but David fears precious time has been lost.

The massive interest in Gabby Petito's disappearance has left him with mixed emotions.

"To become a national story, to have the FBI and other agencies working on it, it's everything I wanted for my son," he says.

"The sad part is the family had to grieve the outcome [her death], but they have a little sense of closure. I don't have any."

Lauren Choimage source, Facebook: Find Lauren Choimage captionLauren Cho went missing on 28 June in California

When his friend Lauren Cho walked away from their bus, Cody Orell saw that she was upset about something, but did not think much of it.

"I didn't pry into it then, but of course now I wish…" he told the local Hi-Desert Star newspaper in July.

Known to her friends as "El", Ms Cho, 30, sang soprano as a teen and went on to become a music teacher.

In search of a fresh start, she quit her job over the winter and joined Mr Orell's cross-country road trip.

She reportedly planned to run a food truck at their final destination: Bombay Beach, California.

But later, the duo would use their converted bus as living quarters and Ms Cho would become a private chef to her friend's Airbnb nearby.

On 28 June, when she walked away from their bus home, she took no phone, food or water.

Search and rescue operations could not even find her tracks. A police helicopter has found no trace.

The Petito case has drawn interest anew in Ms Cho's disappearance.

On a Facebook page called "Find Lauren Cho", its administrators wrote: "We realise that on the surface, the public information for both cases share some similarities. Ultimately, these two cases are NOT the same and the differences run deeper than what meets the public eye."

"Somebody knows something," they concluded hopefully.