(CNN) -- Crew members on a U.S.-flagged ship learned Friday that their questioning by Venezuelan investigators in an arms trafficking probe has been delayed until Monday. Venezuelan authorities have held the ship in Maracaibo since August 29, and took its captain into custody on Wednesday. The shipping vessel's crew had expected to give depositions on Friday, according to a crew member who asked to remain anonymous because of security concerns. As of Friday night, prosecutors had yet to make a decision on the case, according to a manager of the ship's customs brokers. The manager asked not to be named because of the sensitivity of the situation.
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NEW: Captain returned to vessel to move ship from docks, source says
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U.S. official says incident is about paperwork for rifles they had aboard for protection
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The crew's scheduled depositions are pushed back to Monday, a crew member says
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A manager of the ship's customs brokerage firm identifies the captain as Jeffrey Raider
At a previous @placeholder port, authorities sent divers twice to inspect the ship's hull.