A week after the start of the Israel-Hamas war, the killing of a 6-year-old boy, in what authorities say is a targeted hate crime in reaction to the conflict, is alarming many Muslims and Arab Americans who worry that the conflict could fuel a rise in hate crimes against them.

Six-year-old Wadea Al-Fayoume was killed when he was stabbed 26 times and his 32-year-old mother, Hanaan Shahin, was stabbed over a dozen times inside their Chicago-area home, according to the Will County Sheriff's Office. Both are Palestinian Americans. Officials said their 71-year-old landlord, Joseph M. Czuba, allegedly targeted them "due to them being Muslim and the on-going Middle Eastern conflict involving Hamas and the Israelis."

Czuba appeared in court for the first time on Monday for a detention hearing and has been assigned a public defender. His charges include first-degree murder and two counts of hate crimes.

The stabbing death in Plainfield Township, a town of 34,000 people, quickly reverberated across the country, harkening many Muslim and Arab Americans to the days immediately after 9/11.

"There's only two times in my life when my mom has called me and told me 'be careful' in America. And it was a couple days after 9/11, and it was yesterday," said a very solemn Amer Zhar, a Palestinian-American usually known for his comedy.

He says he fears what authorities allege happened is not a "lone wolf" scenario that some are labeling, but a "product of the environment that's been whipped up politically and in the media for the last week."

"Everybody seems to be treating it like world history started on Saturday," says Zhar. "So, while we're scared now, we're really scared about what's to come… Because when you can dehumanize people like this so simply, who knows what you can do to them and then justify it in the eyes of the world."

He says he feels like he's had to be more careful with his surroundings in the last week.

For others, they say the aftermath of the war in Israel and Gaza has forced them to confront possibly changing how they openly identify with their religion. Morgan Fowler lives in West Virginia, and converted to Islam three years ago, said she began wearing a hijab, but says it had never been inherently popular, and always a "bit scary."

But since the war started, Fowler said her colleagues have been walking her to her car after work.

And then she said things took a turn for her after Wadea’s death. She said she confided in the religious scholar who helped her to convert to Islam about navigating during the current Israel-Hamas conflict. She says he advised her to remove her hijab for her and her young daughter’s safety.

"I haven't taken it off yet, but it has crossed my mind… The reason that I really do consider it is because I am a mother, and me is one thing -- but she -- she is a child."

She says learning about 6-year-old Wadea changed how she thinks about her own 9-year-old.

"Seeing this incident over the weekend happening in Chicago where the little boy was stabbed over 20 times made it a little bit more real for me," she said. "As my daughter walks beside me, it's symbolic that I'm Muslim and she could too, encounter some type of violence."

Even in New York City, one of the most diverse places in the world, Muslims leaders are saying they are scared and fear violence.

New York Assembly member Zohran Mamdani, who is Muslim, said, "...friends of mine and constituents of mine, they call and then they just start crying. People are consumed by heartbreak."

"This is eerily reminiscent of the months after 9/11," says Mamdani. He cited incidents in Bay Ridge, Williamsburg and Queens in the last week, and said he's heard of a Muslim tenant denied housing by a landlord because "he said he didn't want to have a terrorist for a tenant."

Mamdani said he was arrested last Friday while marching with Jewish New Yorkers who led a march to Sen. Chuck Schumer's home while asking for a cease-fire. He said in recent days he has received voicemails with death threats. One, he said, "called for the death of all Muslims and a wish that my first child would have brain cancer and die from that condition."

Just last week, a Muslim woman wearing a hijab, who only wants to be described as S.G., saying she fears for family members who work in corporate jobs, says that during a flight from Tampa to the D.C. area one day after the war broke out, a man sitting one row ahead of her stayed turned around, facing her during the entire hour-and-a-half-long flight.

"He did not break eye contact with us whatsoever the entire flight," said S.G.

She says the flight crew picked up on it as well, asking S.G. if she knew the man.

"He [the flight attendant] was worried because he could tell that this guy was you know, just watching our every move and he said, 'I have two daughters,'" said S.G.

After the flight landed, the flight attendant directed authorities on the ground to speak to the man, she said.

A United Airlines representative confirmed to ABC News that this incident occurred.

"It's almost like a microcosm … of what's happening on a larger scale," said S.G. of being watched so closely the duration of the flight.

"Everyone's staring, waiting for a Muslim neighbor or somebody just to say something pro-Palestine or just honor the lives that are being lost. People are afraid…and honestly, it's just really, really heartbreaking," she said.