MIDDLE SCHOOL, MEGHAN SCHILLER, KDKA TV NEWS. >>> IT IS A CONVERSATION A LOT OF PARENTS ARE HAVING WITH THEIR KIDS, THAT SCHOOL SHOOTINGS AND THREATS COULD HAPPEN. A SIGHTINGS OF A MASKED MAN INSIDE BROOKLINE CUT THE SCHOOL DAY SHORT. MAMIE BAH WAS THERE ALL DAY SPEAKING WITH PARENTS. >> Reporter: NOWADAYS IN THE BACK OF NEARLY EVERY PARENTS MIND IS THE THOUGHT THAT WHEN THEY SEND THEIR CHILDREN OFF TO'S WILL THEY MAY NOT COME BACK. TODAY THAT FEAR CAME TO THE FOREFRONT WHILE THEY WAITED HERE FOR SEVERAL HOURS. >> HE IS WORRIED AND HE UNDERSTANDS, WE TALKED TO HIM ABOUT YOU KNOW, WHAT IS HAPPENING. >> Reporter: CLASS BY CLASS, STUDENTS WERE BROUGHT TO THE REC CENTER. THEIR PARENTS AND LITTLE ONES HUGGED EACH OTHER A LITTLE TIGHTER. IT WAS A TOUGH START TO THE SCHOOL DAY, TEARS OUTSIDE THE ELEMENTARY SCHOOL AS THOUGHTS OF A NIGHTMARE BECOMING A REALITY CREPT IN. >> IT SCARED ME TO DEATH. TO KNOW THAT THEY'RE GOING TO GO IN THE SCHOOL ROOM AND I HAVE TO BE SOMEWHERE AND GET A CALL AND SAY I LOSE ONE OF MY CHILDREN. >> Reporter: PARENTS CAN SYMPATHIZE, WAITING ANXIOUSLY AS THE POLICE SURROUNDED THE BUILDING THURSDAY MORNING. THIS IS AFTER THE PRINCIPAL ALERTED POLICE THAT AN UNKNOWN MAN WEARING ALL BLACK INCLUDING A HOODIE AND MASK ENTERED THE BUILDING. WE ARE TOLD TWO STAFF MEMBERS SAW HIM . >> ALL OF THIS IS SCARY. IT NEVER IMAGINE GOING THROUGH THIS. BUT YOU CAN SEE IT ON THE TV AND YOU KNOW IT HAPPENS TO OTHER PEOPLE AND YOU NEVER THINK THAT WHAT HAPPENED TO YOU. >> Reporter: PARENTS SAY THIS IS A GOOD SCHOOL BUT MORE NEEDS TO BE DONE FOR EVERYONE TO BE SAFE BEFORE IT IS TOO LATE. >> I WISH THEY WOULD DO SOMETHING BETTER SECURITY, WHATEVER THEY PLAN TO DO, DO SOMETHING GOOD SO THESE PEOPLE CAN BE SAFE AND DO IT NOW, DON'T WAIT UNTIL ANOTHER SHOOTING HAPPENED. >> Reporter: MOST SCHOOLS DO HAVE SECURITY PERSONNEL TO CHECK IN VISITORS. THEY ARE WORKING ON MAKING THAT HAPPEN HERE. >> THERE ARE THINGS WE CAN DEFINITELY DO TO MAYBE HAVE SOME SECURITY. I WOULD LIKE TO PUT SECURITY PERSONNEL IN THE BUILDING AND HOPEFULLY THAT IS COMING SOON. >> Reporter: POLICE SAY THE MAN WAS NOT ARMED AND AFTER SEARCHING INVESTIGATORS DO NOT FIND HIM. THEY SAY