A bacteria blamed in previous years for killing dogs that consumed it will be investigated as a potential cause of a mystery neurological brain disease observed in New Brunswick that has killed six people, says a researcher involved in the work. Researchers studying the disease plan on looking at cyanobacteria — also known as blue-green algae — and another toxin present in the region to see if there's a link between them and the disease, said Dr. Neil Cashman, a professor in the University of British Columbia's faculty of medicine, who's helping investigate the illness.