The Collaborative International Dictionary of English v.0.48:

Sequestrator \Seq"ues*tra`tor\, n. [L., one that hinders or
   impedes.] (Law)
      (a) One who sequesters property, or takes the possession
          of it for a time, to satisfy a demand out of its rents
          or profits.
      (b) One to whom the keeping of sequestered property is
          committed.
          [1913 Webster]

Bouvier's Law Dictionary, Revised 6th Ed (1856):

SEQUESTRATOR. One to whom a sequestration is made.
     2. A depositary of this kind cannot exonerate himself from the care of
the thing sequestered in his hands, unless for some cause rendering it
indispensable that he should resign his trust. Louis. Code, art. 2947. See
Stakeholder. Sequestrators are also officers appointed by a court of
chancery, and named in a writ of sequestration. As to their powers and
duties, see 2 Madd. Ch. Pr. 205, 6; Blake's Ch. Pr. 103; Newl. Ch. Pr. 18,
19; 1 Harr. Ch. 191.