Former Lehigh University student Yukai Yang admitted to poisoning his roommate to try to kill him.

According to Northampton County Deputy District Attorney Richard Pepper, 24-year-old Yang has pleaded guilty to attempted first-degree murder. 

Yang, a chemistry major, purchased thallium in March 2018. He began putting small amounts in his roommate Juwan Royal’s food, drinks, and mouthwash.

Thallium is odorless and tasteless and highly toxic. Royal was diagnosed with heavy metal poisoning in April 2018. He testified in an earlier court hearing that he suffered weight loss, headaches, and nausea.

Yang’s motive for poisoning his roommate is not known. However, months before the incident, Yang was charged with ethnic intimidation for allegedly damaging his roommate’s TV. Royal is Black and Yang has been accused of writing racial epithets on the former’s belongings.

Yang will be sentenced on January 21 and faces from six to 20 years in state prison. He is not a US citizen and his student visa was revoked after his arrest. Yang also likely faces deportation to China.