India, Oct. 16 -- The escalating criminal investigation into US Representative Ilhan Omar took a dramatic turn as federal authorities seized the Minnesota lawmaker's mobile phone and issued more than a dozen grand jury subpoenas, including demands directed at her relatives.

The sweeping investigative steps follow the execution of a search warrant at Omar's Washington residence by federal agents, intensifying a high-stakes legal battle just weeks before the November midterm elections. The probe, centered on potential immigration and financial disclosure irregularities, has immediately ignited a fierce political storm across Capitol Hill regarding the boundaries of federal law enforcement and executive oversight.

The timing of the aggress...