In the Young case, for example, the complaint states that Leo alerted the officers to the car seat.
A few days later, a hunter spotted the burnt-out Fiat and alerted authorities who discovered the macabre scene inside.
After one user spotted footsteps in the snow near the edge of a cliff, Tomnod alerted law enforcement.
"on the watch," 1590s, from French alerte "vigilant" (17c.), from phrase à l'erte "on the watch," from Italian all'erta "to the height," from erta "lookout, high tower," noun use of fem. of erto, past participle of ergere "raise up," from Latin erigere "raise" (see erect). The adjective is attested from 1610s, the noun from 1803, and the verb from 1868. Related: Alerted; alerting.