Mint Butterfield, the 16-year-old daughter of Slack's billionaire Co-founder Stewart Butterfield, who went missing on April 21 was found on April 27 in San Francisco, police said. She was uninjured and detectives confirmed she had run away from her home voluntarily. Her 26-year-old male friend Christopher 'Kio' Dizefalo was arrested for multiple criminal violations, police said.