For the past two years a grand jury has been looking into the diversion of building materials purchased at Home Depot for housing projects.
Sources say perhaps millions of dollars worth of materials went out PHA's back door. And they say investigators are looking into the possibility that Greene may have been involved personally.
The allegations don't surprise PHA board member Patrick Eiding.
"This is the kind of thing that happens when you have a lot of people that touch a lot of materials and those kinds of things and that can happen. Whether it goes all the way to the top or not, who knows."
Greene's lawyer says he hasn't been questioned by the FBI and hasn't been told he's the target of an investigation.
Investigators say some of the missing materials ended up in a building being renovated by a convicted drug dealer in West Oak Lane.
Other PHA supplies allegedly went into extensive renovations in a house in the Northeast. It was owned by a PHA materials coordinator who's also the son of a Philadelphia judge. He was fired shortly after the investigation started.
The PHA board says it was unaware of the federal investigation.
Eiding says he's now concerned about possible abuses created by Greene's consolidation of power.
Greene created a number of shadow organizations within PHA while edging out most of the contractors who did PHA's building projects.
"There were probably a lot more developers who were doing some of the things that the PHA was doing and when Carl took the initiative to do the things through the authority itself he became the developer," said Eiding.
A developer with no one looking over his shoulder.
"A whole lot could still come out of this before this is all over," said Eiding.
Along with the FBI federal housing auditors are also poking into every corner at PHA. Sources say it will be months before all the investigations are wrapped up.