Monday marked four years since the deadliest high school shooting in the country's history.

Nikolas Cruz opened fire on students and staff at Marjory Stoneman Douglas High School in Parkland, Florida, on Valentine's Day 2018.

A total of 14 students and three staff members were killed. The shooter, Nikolas Cruz, has pleaded guilty and is facing the death penalty.

Many of the students who survived the shooting have become gun control advocates

Long Island native and geography teacher Scott Beigel was killed during the shooting.

His mother has now become a gun control advocate.

Linda Beigel Schulman told News 12 she fought to get gun safety legislation passed on the state level but hopes to see it done on a federal level.

She says she is especially concerned with the rise in gun violence and ghost guns, untraceable firearms that can be bought online and assembled at home.

"It's so easily obtained and so easily put together," Beigel Schulman says. "It must be passed; it must be federal legislation passed banning ghost guns.""

She says she met with President Joe Biden and that he is dedicated to ending gun violence and is in favor of legislation against ghost guns.