Earlier, police said Day carjacked a 16-year-old. He then entered the Walmart, which is about 65 miles south of Seattle, and fired at least one shot at a display case. No one in the store was injured.
Day, 45, then left and shot Fievez, trying to carjack Fievez.
Police: Armed civilian took down shooter at Washington state Walmart
Records show Day has seven felony convictions in Washington dating back to 2001 and at least three gross misdemeanors going back to 2004. He also had convictions for malicious mischief and a failure to comply case from 1993.
He was released from prison March 1, 2016 and was put on community supervision until October 2, 2017, according to the Department of Corrections.
A GoFundMe account was set up to help with medical expenses.
KIRO 7 reporter Michael Spears contributed to this report.