It's a circumlocution commonly used by the FBI meaning that you didn't pass the polygraph.

It's standard procedure to interrogate and seek an admission when an applicant's polygraph charts are scored as "deception indicated." If your polygrapher did not accuse you of deception and interrogate you at the conclusion of your polygraph session, it would suggest that he did not score your charts as "deception indicated." However, it's possible that his decision was over-ruled by the FBI HQ polygraph unit.

You might try calling your applicant coordinator and asking for clarification regarding the letter you received.