The U.S. Holocaust Museum has released a statement on the death of security guard Stephen Tyrone Johns, who died this afternoon after being shot at the museum by a suspect who has been identified as James Wenneker von Brunn.

Officer Stephen Tyrone Johns died heroically in the line of duty today. There are no words to express our grief and shock over these events. He served on the Museum’s security staff for six years. Our thoughts and prayers go out to Officer Johns’ family.

We have made the decision to close the Museum tomorrow in honor of Officer Johns, and our flags will be flown at half mast in his memory.

FOX 5 reports that Johns was 39 years old. A memorial Facebook group has already been created. We’ll update as we learn more about Officer Johns and any memorial activities in the city.