Several Massachusetts communities have increased the police presence at their schools after a shooting at a Texas elementary school left 21 dead – including 19 children – dead.In Newton, the additional presence is part of an ongoing collaboration with police and the local school community.“Officers who have schools assigned to them will give those schools extra attention if they can. They are always on the move and that is why we ask the public for their help,” Newton police Lt. Bruce Apotheker said.Apotheker said what is most important is for children and adults to feel comfortable enough to report when they see or hear something that is concerning. In Tewksbury, police brought in Officer Waffles to help ease some of the anxiety of students at Winn Middle School.Sudbury police were patrolling in and around school properties at Wednesday morning's drop-off to provide comfort and calm fears. “I call it a comforting presence,” Sudbury police Chief Scott Nix said. “It's a balancing dynamic, making sure we have people feel safe, that they are safe while still having a positive educational experience.”Norwood schools are also seeing additional police. While many communities already have school resource officers, they added presence today to address any concerns.In some communities, school safety is going beyond police officers on campus and counselors. In Attleboro, the new high school was designed with the latest security technology and has fewer entrances than traditional schools. The main entrance will have a lobby where reception staff are protected behind bullet-proof glass, and halls and classrooms are equipped with electronic sensors that can detect gunshots.A company based in Rowley, Massachusetts, makes the system, which also calculates where the shots are coming from.“So, we're going to be able to tell you within 40 feet of that sensor where that shot occurred,” said Rich Onofrio of Shooter Detection Systems Inc. The system costs about $500,000 and has an annual service fee of $20,000. “Because, historically, when there were school shootings, the police might not know for five to 15 minutes that there's even an active shooter. And at that point, that's when they start to respond,” Mayor Paul Heroux said.Security analyst Todd McGhee said metal detectors and shot detectors can only react to shootings. He said schools would be better off using technology to look for potential shooters before they pick up a gun.“We should be looking at things like social media, monitoring for threats. Algorithms can detect certain keywords, certain key phrases,” he said.Heroux said the schools are also looking into installing weapon-detection systems. They are not airport-style metal detectors, but are turnstiles that scan people as they pass through.