The co-founder of messaging service WhatsApp, Brian Acton, took to Twitter on Wednesday to say that people should delete their Facebook accounts. Acton, who founded WhatsApp along with Jan Koum, left the company in 2017, three years after the social media giant bought the company for $16 billion (1.04 lakh crore).

His statement came in the wake of revelations that Cambridge Analytica – a company credited with helping Donald Trump win the 2016 United States presidential elections – obtained the information of 50 million Facebook users.

Acton was WhatsApp’s head of engineering and was reportedly a big advocate for the app’s push into encryption. It is unclear if his cynicism about Facebook extends to his own app. Last month, he invested $50 million (Rs 326 crore) in Signal, an independent alternative to WhatsApp, Wired reported.

Acton is not the first Facebook employee to air his misgivings about the company. Last year, Facebook’s former head of growth Chamath Palihapitiya warned that the app was one of the tools that was ripping apart “the fabric of how society works”.

Former executives such as Sean Parker and Justin Rosenstein, and investor Roger McNamee have also warned about the direction Facebook has taken.