U-S Marshals think a wanted man could be hiding in campgrounds located in northern Wisconsin.  Thirty-eight-year-old Dallas Christel is wanted for sexual assault, strangulation, suffocation and several other offenses.  The federal agents are asking campers to be on the lookout for Christel this summer.  He’s been on the loose since March.  Searchers say he raped and strangled a woman in New Holstein last year.  He’s been accused of narcotics violations on several occasions.  The feds say he also has ties to Michigan and Colorado, but they think he is in this state.