Assemblyman Vito J. Lopez, a long-serving Brooklyn Democratic leader who is widely viewed as the borough's patronage king, is at the center of two separate federal investigations, according to several people briefed on the matter. A third inquiry, by the city's Department of Investigation, those people said, is focused on a network of nonprofit groups Mr. Lopez controls.

All three investigations focus to some extent on the nexus of politics, nonprofit groups and real estate developers in Brooklyn, the people familiar with the inquiries said. They spoke on the condition of anonymity because the investigation was continuing.

''The name of the game'' is real estate development, one of the people said, adding that the inquiries have produced masses of records, and in several of the cases the authorities have ''mounds of paper to go through.'' The person would not name the developers under scrutiny, saying only, ''There is a lot of developers in the game here.''

One of the federal investigations began about two years ago, growing out of a corruption case brought by federal prosecutors in Manhattan and the Federal Bureau of Investigation that led to guilty pleas by Assemblymen Brian M. McLaughlin in 2007 and Anthony S. Seminerio in 2009, two of the people said. Mr. McLaughlin cooperated with the authorities and provided information that led to the case against Mr. Seminerio.

To varying degrees, several of the people said, the three inquiries are examining the sprawling social services organization controlled by Mr. Lopez, who in the 1970s and '80s built the prototype of the modern big-city political machine.

The organization, the Ridgewood Bushwick Senior Citizens Council, is expected to receive about $75 million in city funds this year. It is largely through the group that Mr. Lopez's Brooklyn Democratic machine has been able to generate thousands of votes and armies of volunteers.

A spokeswoman for Mr. Lopez, who was first elected to the Assembly in 1984, did not return several telephone calls seeking comment.

Mr. Lopez has not been charged with any crime, and few details about the nature and scope of the two federal investigations are known. The Department of Investigation inquiry has focused on accusations of a range of financial improprieties at the group and related nonprofits.

A 10-page Investigation Department report dated July 20 said members of the organization's board had no experience in nonprofit groups, providing social services, fiscal oversight or serving on such a board. In interviews with investigators, they said they took part in the group's bingo and dancing programs.

The report also described what it called ''fraudulent activities,'' weak oversight and accounting irregularities at a related nonprofit group.

Several of the people briefed on one or more of the investigations played down any suggestion that the number of separate inquiries indicated a dispute over how to proceed in the case. They said that none of the cases had reached a point where criminal charges were imminent.

Mr. McLaughlin, who was president of the Central Labor Council while holding his elected post, began cooperating with prosecutors after his indictment in 2006 on charges that he and his associates looted more than $2 million from the state and nonprofit and union groups, including a Little League.

He provided information that led to charges against Mr. Seminerio in 2007. Mr. McLaughlin was later sentenced to 10 years in prison. Mr. Seminerio pleaded guilty to fraud charges in 2009 and was sentenced to six years in prison.

Mr. McLaughlin is apparently continuing to provide information to the federal authorities. Online records of the United States Bureau of Prisons recently indicated he was ''in transit,'' and now show that he is not in the bureau's custody. One person briefed on the matter said he was being held in a New York City jail and was talking to investigators.

Neither Manhattan federal prosecutors nor Mr. McLaughlin's lawyer, Michael F. Armstrong, would comment on whether he had played any role in the investigation of Mr. Lopez and Ridgewood Bushwick.

The second federal inquiry, which began more recently, is being conducted by prosecutors in Brooklyn and agents of the United States Department of Labor's Office of Inspector General.

When it comes to Brooklyn Assemblyman Vito Lopez, the deeper you dig, the more muck you find.

The latest: yesterday's Post report on how the Ridgewood Bushwick Senior Citizens Council, which he founded, "bought" 25 buildings from the US government for all of $10 -- to be used, supposedly, for subsidized housing.

Actually, it was just one more way for King Lopez to maintain his iron grip over his Kings County realm.

A Lopez aide said the assemblyman, who doubles as Brooklyn's Democratic Party chairman, had nothing to do with the purchase. And Lopez no longer maintains any official ties to the group.

Plus, Lopez has steered truckloads of public cash to the group -- even as several probes examine its operations.

Gov. Paterson and Mayor Bloomberg have now frozen millions in contracts to Ridgewood Bushwick. But Lopez, like other pols who abuse their access to public funds, won't be stopped until he's locked out of the public fisc entirely.

Preferably, officials -- at City Hall and in Albany -- will scrap lawmakers' "member item" slush funds altogether.

But while hell is freezing over, Staten Island DA Dan Donovan, who's running for attorney general, has a useful plan: Force pols to state, under penalty of perjury, that they have no personal ties, financial or otherwise, with any group they plan to fund using taxpayer dollars.

That would build on current AG Andrew Cuomo's "Disclosure & Accountability Certifications," which require disclosure of conflicts by officials at nonprofits -- but not by the lawmakers who fund them.

Donovan's idea could weed out some of the flagrant abuse by folks like Lopez.

True, most lawmakers will resist any attack on their ability to, in effect, buy political support with your tax dollars.

But with Election Day nearing, New Yorkers should demand to know if their assemblyman or state senator backs Donovan's idea -- and then vote accordingly.

Voters often reward representatives for bringing home bacon, but they dislike the system. If Lopez & Co. can't be ousted for abusing it, maybe those who uphold that system can.