The DC shooter who opened fire at his apartment gym and them shot himself was not a deranged migrant but a wealthy emergency room doctor. According to reports, Dr Matt Lambert has been posting on social media on the infestation of black mold in his $1.1 million painthouse and his “manifesto” posted shortly before he opened fire was also about a suspected microbial growth.“My manifesto is an engineering report,” an X account linked to Lambert tweeted Thursday morning. The X account (ofmiceand mold) was full of his posts on molds and other grievances related to his apartment. Last year, Lambert had sued Metropole Condominium Association aleeging that repairs to the building led to mold festering in his home as the building was scaffolded.“Two years of living in luxury (and the start of 6 months with no shower, dryer, HVAC, and cooking),” an X account linked to Lambert posted Wednesday, along with pictures showing renovations in the Logan Circle unit.New York Post reported that Dr Lambert lived on the 7th floor of 1515 15th St NW. On Wednesday morning, he opened fire at the ground-floor gym killing at least one person. Then he ran back up to his apartment where he remained in hiding or nearly an hour before he killed himself.Lambert described himself as “a board-certified emergency physician with over two decades of clinical experience” and a medical tech executive on his personal website. “He has a deep understanding of healthcare regulations and their impact on technology adoption,” the site says.He also said he divided his time between the “mountains of West Virginia and the Logan Circle neighborhood of Washington, DC.”Ward 2 Council Member Brooke Pinto, who represents and lives in the area, said preliminary information suggests the shooter was targeting someone in Vida Fitness and “that he had been in active litigation with over a condo issue.” It’s just so sad and so senseless to kill someone over a dispute that should be worked out reasonably,” she told NBC News.