The pounding on the front door woke up the Xi family in the spring of 2015. Startled, Xiaoxing Xi, a Pennsylvania physics professor and naturalized U.S. citizen, let in federal agents. They charged in with guns drawn and led the father of two away in handcuffs while his terrified family, still in their pajamas, watched in shock and confusion.

The Justice Department charged Xi with passing sensitive technology — used in his superconductor research — to China.

“We were really scared, even though my dad had done nothing wrong. The most powerful government in the world was trying to criminalize my dad,” said his eldest daughter, Joyce Xi. “I couldn’t believe this was happening. It was so traumatic for our family.”

Months later, the government dropped its charges. After a string of cases where Chinese American scientists have been accused of spying for China, Xi worries the pattern will continue, devastating more families like her own.

In a petition at www.scientistsnotspies.org, Xi, now working at San Francisco’s Asian Law Caucus, calls on President Obama and Attorney General Loretta Lynch to cease unjust criminal prosecutions of Asian Americans, to apologize to those wrongfully charged and to investigate whether there is an underlying racial bias at the Department of Justice. Members of Congress, including Rep. Mike Honda of San Jose and Rep. Barbara Lee of Oakland, have also called for an inquiry.

On Tuesday, Aug. 9, her father and leaders from the Chinese American, Japanese American and Muslim American communities are expected to speak at City College’s Chinatown campus, discussing how immigrants have been labeled as threats to national security, the importance of building coalitions to combat injustice, and how people can protect themselves.

These efforts are urgent at a time of rising anti-immigrant sentiment, growing cybercrime and economic espionage, and a burgeoning American rivalry with China. The high-profile prosecutions of Asian Americans like Xi have helped galvanize Chinese Americans to join the fight against racial profiling, be it “driving while black or brown,” “downloading while Asian” or “flying while Muslim.”

Though Chinese Americans have been convicted — including an FBI electronics technician who this week pleaded guilty to passing sensitive information to an official in China — the actions of a few don’t define a community. The government can do more to understand the science central to its charges against these researchers.

The government dropped its cases against hydrologist Xiafen (Sherry) Chen and biologists Guoqing Cao and Shuyu Li, among others, and perhaps most notably Wen Ho Lee, the weapons lab scientist suspected of stealing nuclear secrets in 1999.

Lee spent nine months in solitary confinement. All charges were dropped except for one — improper handling of restricted data— and he received a $1.6 million settlement of his suit against the federal government and several media organizations.

More than a decade and a half later, Joyce Xi is continuing that fight against injustice. “As scientists, we think the (government’s) evidence should speak for itself. It didn’t,” she said. “We are still trying to seek the truth, an explanation, but we can’t even have that.”

Xiaoxing Xi’s attorney has said that federal authorities misunderstood the science behind the professor’s work, as well as the meaning of the emails he exchanged with people in China.

“When we received new information in (Xi’s) case, we acted accordingly and dismissed the charges,” said Lou Lappen, an assistant U.S. attorney. The Justice Department “does not take race, religion, or national origin into its investigative or prosecutorial decisions.”

Xiaoxing Xi and his wife, also a physicist, came to America to pursue research and the opportunities in the United States. They’d both suffered during the tumult of the Chinese Cultural Revolution; after graduating from high school, Xiaoxing, then a teenager, had been forced to shovel pig manure in the countryside.

Their daughters grew up around laboratories. Wearing goggles and a lab coat became second nature, said Joyce Xi. For fun, sometimes her father would demonstrate simple experiments, and she and her sister would get to play with liquid nitrogen and dry ice.

This spring, Joyce Xi graduated from Yale University with a chemistry degree. Rather than pursue a job in that field, she felt compelled to work on civil rights issues. “I grew up learning about the values that America supposedly lives by, but I felt like everything I had ever learned had been violated.”

Even though her father has returned to work at Temple University, she worries that people will still question his loyalty. But the issue is more than personal. In the Bay Area, with its strong social justice movement, she has been connecting with communities that have been demonized, Japanese Americans who were forced into internment camps during World War II and Muslims accused of terrorism after the attacks of Sept. 11.

“My parents, immigrants who worked to make a better life and to better this country, were seen as suspicious,” she said. “But it’s a threat to the fabric of this country to be anti-immigrant.”

Vanessa Hua’s column appears Fridays in Datebook. Email: datebook@sfchronicle.com