The Collaborative International Dictionary of English v.0.48:

Arrestee \Ar`res*tee"\, n. [See Arrest, v.] (Scots Law)
   The person in whose hands is the property attached by
   arrestment.
   [1913 Webster]

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

ARRESTEE, law of Scotland. He in whose hands a debt, or property in his
possession, has been arrested by a regular arrestment. If, in contempt of
the arrestment, he shall make payment of the sum, or deliver the goods
arrested to the common debtor, he is not only liable criminally for breach
of the arrestment, but he must pay the debt again to the arrester. Ersk. Pr.
L. Scot. 3, 6, 6.