threaten note leave weekend las vegas office republican u.s. senator nevada may cast decisive vote healthcare bill aim dismantle obamacare police say monday officer respond burglary alarm build house senator dean heller office find note near office door sunday morning las vegas metropolitan police department say statement content note release police investigate alarm trigger motion sensors force entry build heller office spokesman officer larry hadfield say phone heller re-election next year pressure potential vote revise bill senate would roll back 2010 affordable care act former democratic president barack obama signature domestic accomplishment popularly know obamacare heller among dozen republican senators express reservations remain noncommittal revise bill republicans control senate 52-48 margin afford lose two within rank unite democratic opposition two republicans already say oppose senate majority leader mitch mcconnell delay vote retool bill heller office decline comment letter cite ongoing investigation threaten note leave senator 's office amid healthcare debate