A Florida father said his infant daughter had unexplained hair loss before he caught his neighbor, ex-chemistry student Xuming Li, on hidden camera using a syringe to squirt poison under his door.

"After we caught him on camera, her hair loss became normal," Umar Abdullah, 36, told Fox News Digital. "So, now we think it was a result of the attack."  

He and his wife also noticed that their hair had been thinning, finding clumps on their pillows and in the shower drain.

The Abdullahs began to endure unexplained and alarming bouts of illness in June in their Tampa apartment. 

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Xuming Li show with syringe in surveillance footage next portrait of Abdullah family

Umar Abdullah, his wife Samira and their infant daughter were sickened after Xuming Li allegedly injected poison into their Tampa, Fla., apartment. (Umar Abdullah/Facebook)

His little girl, less than 1-year-old at the time, would refuse to eat and would vomit while he and his wife suffered headaches and dizziness.

Their symptoms were always preceded by noxious fumes that seemed to waft in from the front door.  

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Abdullah installed a hidden camera in a plant outside, which captured Li, a former University of South Florida student (USF), crouching in front of their door and allegedly injecting a toxic substance. Preliminary tests conducted by a hazmat team detected the opioids methadone and hydrocodone.

Li was arrested June 27 on battery, burglary and other charges and released two days later. USF expelled him Aug. 23, one semester before he was set to finish his doctorate, court papers show.

Xumong Li shown crouching down with a syringe.

Screenshot of ex-chemistry student Xuming Li allegedly injecting opioids under his neighbor's door over a noise dispute.   (Umar Abdullah)

Abdullah, who works as an administrator at USF, said he was stunned to learn in a letter from the university that Li had admitted he used a campus chemistry lab to "mix and load the liquid into the syringe on multiple occasions."

Li, who lives below the Abdullahs, had been complaining about noise, from a squeaky toilet seat to the dragging of furniture and heavy footsteps, for more than a year since the couple moved in in June 2022.

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Abdullah tried to accommodate his neighbor, and their relationship initially remained civil, with Li even giving them gifts after their first child was born in August of last year.

The detail that has left Abdullah most shaken is that Li has a family of his own. Li lives with his wife and two children who are both under the age of 2.

A headshot of Umar Abdullah next to a screenshot of Xumong Li holding a syringe outside his door.

A split of Umar Abdullah and Xuming LI, who is accused of injecting deadly opioids under the door of Abdullah's apartment. (LinkedIn/Umar Abdullah)

"We cannot imagine that a parent could do this. He also knows that a baby will wake up at night. They will cry and throw their toys," he told Fox News Digital.

Although Li is now facing charges, the nightmare for the Abdullah family is far from over. 

While preliminary tests indicate the presence of hydrocodone and methadone in the mixture, some experts have said that these two drugs would not produce all the symptoms the family suffered, Abdullah told Fox News Digital.

The family is still awaiting a comprehensive toxicology report from the FBI and fears the little girl could suffer long-term effects from exposure to the chemicals.

Xumong Li stares stonefaced wearing an orange jumpsuit

Xuming Li, 36, shown in a booking photo after his arrest for allegedly injecting deadly toxins under the door of his neighbor, Umar Abdullah, sickening an infant girl. (Hillsborough County Sheriff's Office)

"I pray to God that lab results find that there were chemicals that won’t cause any harm," Abdullah said. "I don't want my baby’s health to be jeopardized."

After Li's release, he returned to his apartment. 

"We feared he'd attack us again," Abdullah said. "It was terrible. One of us never goes out by ourselves or stays alone at home."

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A homeowners' association filed a lawsuit to kick out Li, and, at some point in August, he moved out, Abdullah said. The apartment has been listed for rent on Zillow. 

"The trauma is still here," Abdullah added.

Li's attorney declined to comment. A a university spokesman said the "safety and well-being of the USF community is our highest priority."

He added that the campus' chemistry labs do not stock hydrocodone or methadone.