On Tuesday, a married couple, their 1-year-old daughter, and their family dog were all found dead on a remote Northern California hiking trail. Initially, investigators admitted they were stumped by the case, but they’re now working on a theory that could explain the tragedy. According to the Associated Press, investigators are looking at whether toxic algae blooms in nearby waters are linked to the deaths. The State Water Resources Control Board confirmed Thursday it was testing waterways in the area for any signs of dangerous algae or other toxic substances. The family was identified earlier this week as John Gerrish, Ellen Chung, and their 1-year-old daughter, Miju. A friend of the family told the San Francisco Chronicle: “They were such a loving couple, they loved each other quite a bit... He loved showing the baby all sorts of things and explaining them to her.”