Twenty years after a series of murders by the so-called “I-70 killer,” police in one St. Louis suburb are releasing new information in the cold case.

Thursday marks the 20th anniversary of the death of 24-year-old Nancy Kitzmiller. She was found by customers at Boot Village in St. Charles, where she worked.

Kitzmiller was 1 of 6 people killed in five Midwestern cities in April and May of 1992. 4 of the murders were at small shops along Interstate 70 – two in Missouri, two in Indiana. The other two were at a bridal shop near Interstate 35 in Wichita, Kan.

St. Charles police say that based on ballistic evidence and witness statements, the gun was .22-caliber, possibly an Intratec Scorpion or an Erma Werke Model ET 22.