Up to 16 students at a New York school have been stricken with a mysterious illness characterised by facial tics and Tourettes-like outbursts. The female students, at Le Roy High School first began to show signs of the disorder in August. Neurologists claim the students are suffering from collective psychogenic illness – a psychological disorder with physical symptoms once known as mass hysteria. Chelsey Dumars, 16, told WGRZ-TV about the tics plaguing her. She said: “I hate it when it happens… my body’s sore. Sometimes it gets me to the point I want to cry from twitching so much.” Her father, Dave Watson, said: “How can you send your child to school perfectly normal and a couple of hours later you’re picking her up in this condition?” One of the affected students, 16-year-old Lori Brownell, posted a video on YouTube, detailing how her symptoms began and appealing for help from anyone who might explain her condition. The teenager is unable to attend school because her symptoms have become so severe. Famed environmental campaigner Erin Brockovich has now intervened at the request of parents, MSNBC reported. Brockovich, who was played by Julia Roberts in an Oscar-winning performance, told USA today she was looking into a 1970 train accident that spilled cyanide and an industrial solvent called trichloroethene four miles from the school. The campaigner, who says she has received more than 100 emails from the school, added: "We don’t have all the answers, but we are suspicious. They have not ruled everything out yet. The community asked us to help, and this is what we do." But Brockvich’s representatives were ordered off the school’s property this weekend while attempting to take samples from the grounds. A statement by the Le Roy Central School District, said the police had been called because the unauthorised presence of the sample collector and TV crews had disrupted a planned musical event involving students from 22 other schools. The team was eventually admitted to the grounds, without media, on the condition they did not collect samples.