I'd thought she'd been scared off by Michelle O's own pending announcement, but no, Hillary is serious about running again

One source has the story here, but the clincher can be found at the Babylon Bee:

Hillary Clinton accidentally posts condolences for Tulsi Gabbard’s suicide a day early

U.S.—Oops! A social media scheduling error apparently caused Hillary Clinton to post her condolences for Tulsi Gabbard's suicide one day early.

This morning, Clinton posted that she felt "great sadness" at hearing that Gabbard had killed herself. In subsequent tweets, she detailed how "tragic" it was that Gabbard had broken her own kneecaps, stuck her feet in concrete, then tossed herself off the docks near a seedy warehouse.

"It's just terrible what happened, and though we disagreed, I hope we can all take a few minutes to send thoughts and prayers to the family," Clinton concluded.

The post was deleted several hours later after the Clinton team realized it was scheduled for October 23, not October 24 as originally intended.

At publishing time, Clinton had accidentally posted early condolences for the unfortunate suicide of the social media manager who had OK'd the post and subsequently posted more condolences for the new social media manager, etc.

Vince Foster was unavailable for comment.