Подскажите, как верно перевести фразу из предложения.The technician must be sufficiently

Подскажите, как верно перевести фразу из предложения.

The technician must be sufficiently knowledgeable and experienced with the equipment and process of videotaping to assure the court that all the equipment as in working order, that the tape was not edited, and the proper chain of custody was maintained.


"the proper chain of custody was maintained".