A University graduate died in a single vehicle accident as Unofficial St. Patrick’s Day drew to an end Friday night.

Champaign Police Department officials say Caroline Yoon, 22, fell off the backseat of a motorcycle that crashed at the intersection of Wright and Healey streets in Champaign at 11:53 p.m.

The driver of the motorcycle, Samuel Park, 23, has been charged with a DUI. The accident is still under investigation, and according to Champaign Police officials, further charges may be forthcoming.

Yoon was rushed to Carle Foundation Hospital Emergency Room where she was pronounced dead four hours after the accident.

Champaign County Coroner Duane Northrup said Yoon was not wearing a helmet at the time of the crash, and died of head trauma.

Toxicology tests on Yoon’s blood concerning her blood alcohol level will not be returned for two or three weeks. Park was released on a $1,000 bond early Saturday morning.

At the time of Yoon’s death, Northrup said she was wearing a green t-shirt with the words “Unofficial St. Patrick’s Day” printed on the front. An autopsy of the body was performed Saturday in Bloomington, Ill.

Yoon, who received her undergraduate degree from the University, is from Glenview, Ill., and was enrolled as a graduate student at the University of Pennsylvania.