What search tactic involves crew members moving laterally and forward within their assigned search lanes?

The correct answer is loose grid searching. This search tactic involves crew members systematically moving laterally and forward within their assigned search lanes, ensuring that the area is thoroughly covered. The key characteristic of loose grid searching is that it allows for overlapping coverage, which is vital for not missing any potential clues or signs related to the search subject.

In this method, crews may not be as rigidly aligned with each other as in tight grid searching, which focuses on close, parallel lines. Instead, loose grid searching allows for more flexibility in movement, easing the ability to adjust for environmental factors or obstacles that may arise during the search. The goal is to effectively cover a broader area while maintaining thoroughness.

In the context of other search tactics mentioned, containment searching generally refers to securing an area to prevent the search subject from leaving rather than focusing on within the search lanes. Tight grid searching emphasizes closely spaced lines for a more detailed approach, while systematic search covers a methodical approach that may not specifically involve lateral and forward movements in lanes as outlined in loose grid searching.