New Year's Eve, 04:14pmEST.
CNN reported Saturday that police tracked the suspect in the Idaho murder for days as he traveled across the country for Christmas.
CNN cited two law enforcement sources as saying that law enforcement began tracking the man after they identified him as the owner of the white car.
According to CNN, police surveilled him for several days as he traveled from Washington to Pennsylvania, where he was arrested and charged with four counts of first-degree murder.
Police said that he lived 10 miles from Moscow, Idaho.
Washington State University confirmed Friday that the graduate teaching assistant had finished his first semester as a student in the school's criminal justice program.
After graduating from Northampton Community College in Bethlehem, Pennsylvania, with an associate of arts degree in psychology, he went on to earn a bachelor's degree from DeSales University.
He is expected to be extradited from Pennsylvania to Idaho on January 3.
Washington State University has extended sympathies to the families, friends and Vandal colleagues who were affected by the murders, as well as hopes that the announcement of the arrest will be a step towards healing.
Idaho state law prohibits an affidavit laying out the facts behind a person's arrest from being opened until they return to their home state.
The deaths of the University of Idaho students cast a spotlight on the small farming community of Moscow. Police say four people were stabbed to death in a home near the school. Police were unable to locate a suspect or a murder weapon before releasing a public statement that they were looking for a white sedan that was seen near the murders.
The suspect in the University of Idaho killings was arrested.