WASHINGTON — A U.S. State Department employee pleaded guilty Monday to producing thousands of images of videos of child pornography over a two-year period. Skydance MacMahon, a 44-year-old Alexandria resident, used hidden cameras to produce sexually explicit images and videos of minor children in Canada, according to court documents. MacMahon worked with a woman in Canada to produce the child pornography and distributed the videos and images through cloud storage and email. Police found pornographic images of children on an Ohio man’s cellphone in November 2017, and authorities were able to link Dropbox media of child porn to an account...