Police on Friday applied to officially arrest a postgraduate medical student at Fudan University in Shanghai who they say killed his dormmate.

According to the police statement, the suspect, named Lin, had disputes with his 28-year-old dormmate Huang Yang, another postgraduate medical student, over some trivial matters, so Lin took some toxic compounds from the school laboratory and put it in the water cooler in the dorm.

After drinking the water from the cooler on the morning of April 1, Huang showed symptoms of being poisoned. Despite medical efforts, he was pronounced dead on the afternoon of April 16 from multiple organ failure.

Police did not disclose what the "trivial matters" are or the name of the toxic compound. Previous media reports said the substance was N-Nitrosodimethylamine, which can cause liver damage.

Police said they received school reports of the case on April 11 and held Lin under criminal detention the next day. After an investigation, an application to arrest Lin was made on April 19 to local prosecutors.

According to China's Criminal Procedure Law, an official arrest must get the approval of the local procuratorate.