Is this Penguin or Manual Penalty?

[RonMedlin]

I have a client that's traffic dropped off on April 10th.  They did get a message in GWT on March 21st.  The April 10th date leads me to believe that it is a manual penalty and couldn't be penguin since penguin was released on April 24th.

I guess either way backlinks need to be cleaned up though.

[Andropenis_Australia]

What was the message?

Just because penguin was rolled out on a specific date does not mean you couldn't get a warning early/later on, They want us to think it was released on the 24th, but was it really.......

You are right too, backlinks certainly need to be cleaned up if they are spammy.

[donford]

I will further add, it is common for webmasters to report competition whom are actively engaged in or can be perceived to have participated in black hat tricks. If the report holds credence then, Google can and will "sometimes" manually ding the account. A GWT warning is one indication of that having had happen.

In your case it could be further complications have arose due to the subsequent Penguin algorithm update.