MADISON, Wis. (AP) – Prosecutors have charged a man accused of killing his half brother with intimidating a witness.  According to a criminal complaint filed Thursday, Jeffrey Vogelsberg threatened his grandfather, James Robar, in a letter from jail last week.  Robar called police in July to report that Vogelsberg’s half brother, Matthew Graville, had gone missing. Detectives eventually found Graville’s body buried in the woods. Prosecutors charged Vogelsberg in November with first-degree intentional homicide and hiding a corpse.  According to the new complaint, Robar told a detective Vogelsberg warned him reporting Graville’s disappearance meant war. Vogelsberg sent Robar a copy of the detective’s report on the remark from jail on Feb. 13. Robar said the letter disturbed him.   Vogelsberg’s public defender didn’t immediately return a message.