O, Telefon dinlemesinin üstlerinin emirleri ile yürütüldüğü şeklinde ifade verdi. - He testified that the wire-tapping was carried out at the behest of his superiors.
If something is done at someone's behest, it is done because they have ordered or requested it. In 1970, at his new wife's behest, they moved to Southampton. at the behest of sb because someone has asked for something or ordered something to happen