It's been a rough week for real estate billionaire Sheldon Solow. On Monday, it came to light that Marc Dreier, the lawyer now accused of defrauding investors to the tune of $380 million, had been trying to sell fake Solow Realty promissory notes to investors. (It was Solow, in fact, who first tipped off the authorities back in October.) Now he has a new headache to contend with. Citibank filed suit against Solow this week, claiming Solow has thus far failed to pay back $67 million in loans and $18.5 million in letters of credit. The funds were part of a half-billion loan that Citi extended to Solow in 2004 to finance the development of a series of buildings along the East River waterfront. Unfortunately for Solow, construction on the project hasn't even started yet and it appears he's already running into financial difficulty. The nitty gritty from Citibank, N.A. v. Sheldon H. Solow after the jump.