[T]his letter will serve as notice and demand to you ... to cease and desist any further publication of false information concerning the City of Pomona, the City Council of the City of Pomona, the City Manager and/or any of the City's employees and that you delete and retract all such communications that have appeared on your web-site concerning this matter during the month of April 2007 to the present.
(LA Observed has more on this.)
I can't speak to whether any of the blog posts did indeed libel City employees or officials. But I can say that the City Attorney has no legal basis for demanding (as opposed to requesting, by appeals to a sense of fairness or journalistic standards) that the blog stop publishing false information about the City -- under New York Times v. Sullivan (1964), there can be no lawsuit for libeling a government entity.
The NYT v. Sullivan Court stated that "no court of last resort in this country has ever held, or even suggested, that prosecutions for libel on government have any place in the American system of jurisprudence," and it endorsed this tradition as being constitutionally mandated. So while I certainly think it's wrong to make knowingly or recklessly false statements about government entities, and while it may be libelous to make such statements about particular city employees or officials, it cannot be libelous even to say outright lies about the City of Pomona more broadly.