c.1300, from Old French cerchier "to search" (12c., Modern French chercher), from Latin circare "go about, wander, traverse," in Late Latin "to wander hither and thither," from circus "circle" (see circus). Phrase search me as a verbal shrug of ignorance first recorded 1901. Search engine attested from 1988. Search and destroy as a modifier is 1966, American English, from the Vietnam War. Search and rescue is from 1944.
c.1400, "act of searching;" early 15c., "right to investigate illegal activity; examination of records, wills, etc.; a search through an area or a place," from Anglo-French serche, Old French cerche, from cerchier (see search (v.)). Search warrant attested from 1739.
An exclamation or acknowledgment of ignorance; beats me: Who said it? Search me, I couldn't say (1900+)