The head of BlackBerry Messenger has become the latest in a string of top executives to depart the Waterloo, Ont., smartphone maker.

However, the brief email announcement issued by the company shed little light on the departure of BBM head Andrew Bocking.

"I can confirm that Andrew Bocking, EVP, BBM has made the decision to leave BlackBerry. We thank him for his years of leadership and contribution," company spokeswoman Rebecca Freiburger said.    

"The BBM organization remains a group within BlackBerry and will continue to focus on BlackBerry and BBM strength in messaging and new areas of strength such as mobile marketing, community-building and enterprise messaging."

Freiburger said John Sims, president, Global Enterprise Solutions, who has extensive experience in mobile messaging, would add the BBM team to his organization.

BlackBerry head John Chen has made wholesale changes in the company's executive offices since taking over as chairman and CEO back in November.

In addition to the many long-time executives who have left, Chen has brought in a number many new faces, including many people he has worked with in the past.

BBM, which is currently free to users and does not carry advertisements, is a service that Chen has indicated he wants to monetize. However, he has not said how the company plans to do this.