MONUMENT, Colo.—Authorities believe a man killed his wife and two of his children last weekend before killing himself in an affluent community near Colorado Springs. Yvette M. Siegert-Kreb, 50, Felicity Kreb, 13, Barrett Kreb, 9, and Christof Kreb, 55, were found dead Saturday in their home in the community of Gleneagle, the El Paso County Sheriff’s Office said in a statement Monday. Details about how they died will be made public by the county coroner, the statement said. Alexa Gromko, a family friend since 2010, told The Gazette that Felicity and Barrett were among six children that the couple had adopted from China, most of them dwarfs, after their youngest biological son was born with dwarfism. Felicity had learning and social problems because of dwarfism and Barrett, one of the newest adopted children, had recently undergone surgery, Gromko said. “She wanted her son to feel like he had people like …