Show once in jeopardy is washington the supreme court ot the united states has affirmed the decision of the united states district court for the district of columbia in the cases of william R mason and joseph ander welde who were charged with the murder in 1907 of doseph A walker a special agent ot he department of j estice while in the discharge of his duty walker was killed by Vander welde while standing guard at the mouth of a coal mine in la plata anty colorado and he and mason who was with him the time of the shooting pleaded self de tense |