An ISU graduate student charged with attempted murder will appear in court April 23 after he pleaded not guilty to the charges in Story County Court Friday.

Ziyi Dai, former graduate student in business administration, is charged with attempting to kill his wife, Li Cao, assistant professor of mechanical engineering, in the Black Engineering building in December.

Dai was arrested after Cao arrived at Mary Greeley Hospital with knife wounds to her fingers, hands and arm. The knife believed to have been used was later found in a vehicle.

The original charges of willful injury and going armed with intent stemming from domestic assault were upgraded after police learned of Dai’s attempt to pay a cellmate to kill his wife upon the prisoner’s release.

Although the inmate refused the proposal, he was given handwritten directions to Cao’s residence.

Other inmates have also come forward with confessions from Dai saying he intended to kill his wife.

If convicted, Dai could face up to 25 years in prison.