Just maintain all the details you have available to support the actual loss.
Get this information now in order to have it available in the event the IRS audits your return.
I'm assuming, based on your response, that you were never going to get a K-1 and that this was a one time investment and the sale of the property triggered the recognition of loss event.
This is not a real clear area (crowd funding investments) and one fraught with loose ends and exposure.
*A reminder that posts in a forum such as this do not constitute tax advice.
Also keep in mind the date of replies, as tax law changes.
