The six years sounds very suspicious. I have never heard of a lease going that long.

I wouldn't worry about her losing her job if she is genuine. That is something that can be dealt with by your daughter getting a new place to live.

Tax records as to who owns what property are often available online. Or someone who lives in DC area could check for you.

She should be willing to meet you at her place of work and offer to have you meet her boss or coworkers so you can be convinced of her identity, once you have determined that the person with her name is the actual owner of the property. mg