A shooter walks into your office building, your school, your restaurant, and opens fire.

How would you respond?

Several months ago the Marietta Police Department planned to offer free instruction to residents on reacting to an "active shooter" situation. Most of the department's gun safety seminars are held in the city council chambers, and attract fewer than 200 participants, according to Officer Brittany Wallace, public information officer with Marietta police.

But within a week of announcing the active shooter seminar, the department received 300 reservations. After the shootings in San Bernardino, Calif., the reservations jumped to 500.

The department realized it would need to move to a bigger venue, and reserved the Marietta Performing Arts Center, on the Marietta High School campus, at 1171 Whitlock Ave. Finally the reservations topped out at 800.

The two-hour seminar, which will be held at 6 p.m. on Wednesday, Dec. 9, is currently full, and Wallace didn’t expect to create a waiting list, though she added that some with reservations will typically drop out at the last minute. She said the department will probably schedule another training event some time next year.

Called “Citizen Response to Active Shooter Events” (or CRASE), the seminar is taught by certified officers who’ve been through a training curriculum. The CRASE course uses video and sound recordings from actual shooter events. Wallace said there is no age limit for those attending, but added that parents should be aware that children (and others) may be upset by the recordings.

She said part of the seminar will focus on those who are legally carrying weapons. “They’ll discuss what to do if you are carrying, since we (the police) don’t know the good guys and the bad guys on arrival.”

A nationwide database of mass shootings shows that in Georgia 25 have been killed, 69 wounded so far this year, according to an AJC story that appeared last week.

Last month the Atlanta Police Department conducted active shooter training for officers in the department, and recently staff at Villa Rica High School participated in similar training, but Wallace said she believes this is the first time the training has been offered to the public in the metro area.

“It’s sad that this is necessary, but we want people to be safe,” she said. Referring to the recent attacks in Paris, she added, “People thought France was so far away, and then San Bernardino happened two weeks later.”

For more information call 770-794-5370 or go to the Marietta Police Department.