Three months after a prospective buyer of Downtown Jacksonville’s Laura Street Trio of historic buildings announced he had reached a tentative purchasing deal with the owner, city officials say the sale still hasn’t closed and negotiations have faltered.In mid-January, Live Oak Contracting President and CEO Paul Bertozzi told City Council members he had entered into a purchase and sale agreement with SouthEast Development Group Inc. on the long-vacant structures at Laura and Forsyth streets. At that time, Bertozzi said he expected to close on the deal within 45 days.On March 19, city Chief Communications Officer Phil Perry said in an email that the agreement appeared to have stalled, prompting the city to resume action on a lawsuit alleging SouthEast-affiliated Laura Trio LLC has failed to pay $827,500 in fines for municipal code violations stretching back several years.