If you hold a gun safety seminar, they will come.

The evidence was clear at the seminar offered Thursday night by the Marietta Police Department, a class which usually attracts 100 people, but this night drew more than 500.

From the elderly woman considering her first home defense weapon to the mother wanting to protect her 7-month-old, many people offered the same reason for coming: Times have changed.

They’ve seen too many shooting tragedies on the news, many said; others stressed they want to buy a gun before the federal government tries to curtail that right.

“There’s been an incredible surge of interest in gun ownership,” said Marietta Police spokesman David Baldwin. “We want people to know safety and the laws.”

Angie Bryan’s reaction to the massacre of Sandy Hook Elementary schoolchildren in Newtown, Conn. — “horrible, horrible” — got her thinking about her being a single person who lives alone. She’s not only contemplating buying a gun, she’s considering applying for a permit to carry it.

“I don’t like guns, but I want to protect myself,” said Bryan, a Canton resident who picked up one of the free gun locks offered at the police seminar.

It’s been about 15 years since Sandra Wheeler fired a gun, but the 65-year-old Roswell resident has been troubled by all the recent gun-related crime and violence.

“It seems like it’s getting closer and closer to home,” Wheeler said. “I want to purchase a gun, but I want to know about the laws and safety.”

Such fears extend well beyond those who gathered Thursday in the auditorium of the Marietta Middle School. Gun sales and permit requests have surged across metro Atlanta since the Connecticut school massacre in December, and interest has been further stoked by President Barack Obama’s proposals for the most sweeping gun control in decades.

News reports indicate the demand for guns and permits is climbing in other states as well.

“I want to get a gun before I can’t,” said James Praser, 34, an engineer from West Cobb who brought his 8-year-old son, Luke, to the seminar.

Praser has a hunting shotgun but wants a handgun for home defense. He started thinking about it after he saw the “anarchy and looting” during Hurricane Katrina.

“I worried that some kind of event could lead to that,” he said.

But he’s filled with questions: “Should I keep it loaded? That seems unsafe. I need to keep it accessible, but accessible could mean not safe.”

Marietta Sgt. Jake King, one of the seminar speakers, said that 700 people called and emailed to sign up for Thursday’s talk, prompting the department to shift the event from the City Council chambers to the school auditorium. Police offered estimates that up to 600 people attended. People did not bring or handle weapons during the seminar.

King stressed that when planning for home defense, people need to do a “mental rehearsal” in which they go over where they will keep the weapon, where they will position themselves, and in which directions they can shoot without worrying about a bullet going through a wall and hitting an innocent person.

The speakers emphasized the importance of handling all guns as though they are loaded.

“A lot of people buy a gun who don’t know how to use them,” King said. “And people are getting hurt.”

Sitting in a back row with her infant son on her knee, Lampra Jones of Marietta said she plans to soon buy her first gun.

“I’m a single mom,” she said as she held 7-month-old Solomon. “I don’t have the luxury of telling my husband or partner to go downstairs to see what’s going on.”

She added, “It’s just me and my son, and that’s pretty dangerous.”

Craig Stanchec said he came here for his son, Logan, who accompanied him. He wanted the 11-year-old to learn more about gun safety.

“We do have a gun in the house,” the father said.

Logan said he already knows the first rule about guns.

“Never touch one without my parents’ permission.”