Q: Hi, I just need to know if you can sue or press charges against a TSA agent for sexual assault during a pat down?

A: Sorry to hear about your ordeal. Depends on the facts. The issue would be whether the agent did something offensive outside of the pat-down guidelines that the agency instructs them on. Here is a link to an example of such instructions: https://www.tsa.gov/sites/default/files/foia-readingroom/pat-down_training_procedures_april_2018-1600112rr-1_pt2.pdf . (I don't know if it's up to date.)

Also, for technical legal reasons, if there were to be a civil claim, it might need to be brought against the United States of America, rather than the agent.

Regarding any potential criminal charge, that is something you'd have to discuss with the appropriate law enforcement agency. Not sure if that would be the local police department (for the jurisdiction that includes the airport) or a Federal agency such as the FBI. If you start with the police dept., they'll let you know. An issue they'd need to look at, and any civil attorney would need to look at, is your proof. Is there some kind of evidence beyond you saying it happened, which the agent can simply deny? - such as, were there any witnesses; would a security camera have revealed it; did you promptly complain to someone; did you need any medical attention?, etc.

If you think a security camera recording would be relevant, a written request to the airport to preserve the recording should be sent immediately, as they eventually delete the recordings. They likely are not required to turn over the recording in response to a letter, but they'd then be under a duty to preserve for potential future legal proceedings.