Doubling back

ボストンマラソンで爆弾をしかけた犯人の二人が逃走中にCARJACKをした時の記事（Reader's Digest 8月号）から引用します。
The tank nearly empty, they stopped at a gas station, but the pumps were closed.
Doubling back, they returned to Watertown and grabbed a few more things from the parked car, but nothing from the trunk.
"Doubling back" はその後に "they returned" とあるのと意味は結局同じ気がしますが、この表現を見るのは初めてなので辞書を見ます。
・Collins Dictionary: to go back in the opposite direction (esp in the phrase double back on one's tracks): But he couldn't double back the way he'd come for fear of running into the army patrol.
・Merriam-Webster's Online Dictionary: to turn and go back in the direction you have come from: We realized we had taken the wrong road and had to double back.
・Vocabulary.com: retrace one's course: Others turned sharply as they exited, then doubled back to reconsider.
元来た同じ道を戻る感じですね。やはり、"return" と一緒に使うのは冗長表現の気がします。