An Ottumwa man who once threatened to kill then-President Barack Obama is scheduled to be sentenced in January for threatening a federal judge.  Federal court records say Matthew James Howard has pleaded guilty to threatening the judge and to mailing a threatening communication. His sentencing is set for Jan. 10 in U.S. District Court in Cedar Rapids.  Howard, who is serving prison time for robbery and burglary, received an additional three years in September 2013 for writing letters threatening to kill Obama and a judge earlier that year.  Howard was indicted in April for threatening U.S. Judge Linda Reade in a letter sent from prison in Anamosa in November.