Former Stanford grad student Xiangyu Ouyang accused of poisoning classmates

A graduate student has been arrested and charged in Califoia after she allegedly poisoned herself and her classmates.

Miss Xiangyu Ouyang, 26, attended Stanford's School of Medicine, had put paraformaldehyde (PFA) in her drinking water as well as into her classmates' water bottles.

PFA, a commonly used substance in biology, is lethal if ingested in sizeable amounts.

She has pleaded not guilty by reason of insanity and is no longer a student at Stanford.

The second-year Singaporean student was described as a quiet girl with no friends and had once asked a classmate what it was like to have a boyfriend.

She had graduated from Imperial College London with a degree in biochemistry,

It was revealed in court papers that she had been suffering from severe insomnia, dizziness, depression and a disconnection from reality.

Her parents are believed to be researchers. 

Miss Ouyang had also allegedly destroyed some of the projects that the other cancer biology students were working on.