I believe it points towards pre-planning a murder.
JANUARY 2008 - The New Year starts with Nancy finally finding out the truth of Brad's affair. After months of denials he finally admits it and claims he is in love with H.M. Nancy is 'done' with the marriage and done with trying to work on the marriage.
FEBRUARY 2008 - Brad removes Nancy from all accounts.
MARCH 2008 - Nancy gets Alice Stubbs, Attorney and first draft of separation agreement starts.
APRIL 2008 - Brad realizes he's going to have to pay beaucoup bucks to Nancy. Brad abruptly cancels NC's move back to Canada when previously he couldn't wait for the 3 of them to leave. NC was supposed to leave April 25.
APRIL 2008 - Brad has all of NC's emails forwarded to his own account. From April 2008 through July 11 2008.
APRIL 2008 - Brad is laying some foundation of his own. Finding out how to completely wipe a hard drive (why he had to ask someone else I don't know, but he did).
This is the start of his planning, or, at least where I think it really started to gel in his mind. The 'when' was not set yet, but the thought to kill Nancy was formed, IMHO.