The runaway daughter of Slack co-founder Stewart Butterfield may have been spotted in San Francisco.  Sixteen-year-old Mint Butterfield is the child of the corporate messaging company’s CEO, Stewart Butterfield. 

Mint was reported missing early Monday after fleeing their mom’s home in Bolinas, Calif. — leaving behind a note, the Marin County Sheriff’s Office said.

The teen’s mom, Flickr founder Caterina Fake, alerted authorities immediately after discovering the letter and warned that Mint could have been headed for San Francisco’s notoriously dangerous Tenderloin District neighborhood.

The Sheriff’s office and the San Francisco Police Department are working together to locate the teen.