make off with

Yoko Ogawaの "Hotel Irish" を読んでいます。 不思議な事に（と言うか小説なので）Mariは変態と分かったロシア語老翻訳家と交際を続けています。海水浴に行った後の話です。　色々と物をくすめる癖のあるHotel Irishの女性従業員が今度はMariの水着を盗んだようです。

The maid had worked all day, even staying late. She had waxed the floor in the lobby, cut the grass in the courtyard, and washed the windows in the dining room--all while she asked me disturbing questions.
"What would you do if your mother told you she was getting married again?"
...
"Are you still seeing that boy?"
I answered halfheartedly or pretending not to hear, but she kept after me just the same. She was probably secretly gloating at having made off with my bathing suit. When Mother handed her a can of beer as she was getting ready to leave, she slipped it into her bag--the bag where she must have hidden my suit.

"made off with" はいわゆる句動詞のようですね。ここでは話の前後から「盗み取った」の意味のようですが、辞書で確認します。
・Oxford English Dictionary: to steal something and hurry away with it: Thieves made off with $30 000 worth of computer equipment.
・Collins Dictionary: If you make off with something, you steal it and take it away with you.: Masked robbers broke in and made off with $8,000.
・Farlex Dictionary of Idioms: To escape with someone or something that has been stolen, snatched, etc.: The thieves busted the ATM and made off with the cash inside.

"made off" 急いで逃げるの意味があり、それに "with something" が付いているので持ち去ることになるのですが。しかし、引用した小説の場面は多分盗んではいるが、その後、ホテルの主人、Mariの母から缶ビールをもらって帰るところなので、まだ逃げたわけではない。 "made off with" は盗んで持っている状態でも使えるのですね。