I also received an email update that my file had been transferred to Detroit. The following is my timeline;
We received your application for permanent residence on December 9, 2009.
We reviewed your application and sent you a letter on February 15, 2010. Please consider delays in mail delivery before contacting us.
Your application and supporting documents were received by the Detroit office. They are pending review.
We transferred your application to the Detroit office on February 24, 2010. The Detroit office may contact you.
We transferred your application to the Detroit office on October 26, 2011. The Detroit office may contact you.
This process sure takes a long time. I am hoping that I don't need to get yet another WP.