Do you use the same username everywhere? It's common for criminals to collect lists of usernames and try them in combination with guessed passwords on as many services as possible. The yield is low but it's cost-effective for them because the process is fully automated using thousands of bots and many people use poor passwords.
They may even have guessed the username. First intial-lastname is a common pattern. You have produced no evidence of an actual break-in: merely an attempt. Break-in attempts are very common. -- John Hasler jhas...@newsguy.com Elmwood, WI USA