Normally if you gave up the foreign passport, purchased a burial plot here, funny as it sounds…establishes that you live and will die here. If you have some form of income or social income that could indicate a continuity of ties or loyalty to the former country it slows it down but doesn’t remove the possibility. Obviously most folks not fleeing oppression will have fondness for their roots and mother country. Nothing wrong with that. Almost impossible to disinherit that. If they are considered a friendly country it is easier, if they are Cuba, Iran, Iraq, Russia, etc…it is still possible but will take longer. Owning property overseas can slow things down but plenty Americans have cottages in various locations. Most above board. But expect those areas need scoped to get a reasonable degree of certainty one isn’t more loyal to the other country and wouldn’t funnel information. Sad to say Americans, likely westerners all over do not have an eye on the long game. Countries are willing to send their citizens abroad to live, work, play, educate…matriculate…and gather essential elements of friendly information. Some nations consider it a lifelong responsibility to do so. This is the part that is mysterious and requires probing.