Nassau acting District Attorney Madeline Singas said Thursday she will investigate Nassau County's process for awarding contracts after disclosure of a federal probe into allegations against State Senate Majority Leader Dean Skelos and his son.

Singas' announcement was one of several developments in an inquiry that has the potential to rock not only Long Island but also New York State politics. On Thursday, Skelos (R-Rockville Centre), the state's top Republican, acknowledged the federal investigation for the first time, adding he will "continue to cooperate."

Nassau County Executive Edward Mangano, a Republican, also acknowledged his cooperation though his spokesman, who said investigators have notified Mangano and the county "that they are not targets of the investigation."

StoryPols: We didn't know contractor employed Skelos' sonStoryTitle co. in Skelos probe has supported DemsStorySkelos: Investigation report 'irresponsible'

Skelos' son, Adam, was working as a consultant to Arizona-based AbTech Industries, and had introduced county public works employees to the company, a source said. AbTech Industries received a $12 million storm-water treatment contract from Nassau County in 2013, records show. The company produces technology to remove pollutants and debris from storm-water drainpipes before runoff reaches waterways.

Preet Bharara, the U.S. attorney for the Southern District of New York, is probing whether Skelos exerted any influence in matters involving AbTech, The New York Times first reported late Wednesday, and Newsday reported that Mangano testified last week before a federal grand jury looking into the case.

Singas called the reports "troubling" and promised a "comprehensive review."

advertisement | advertise on newsday

"Today's news about AbTech Industries is troubling and my Public Corruption Bureau will conduct a comprehensive review of Nassau County contracting practices," Singas, a Democrat, said in a statement.

In response to Singas, a Nassau official speaking on background defended the county's contract process: "The county contract process was thoroughly reviewed by [former] DA [Kathleen] Rice's office after [superstorm] Sandy. We have the most transparent process, with numerous checks and balances."

Back in January, Skelos, 67, called news reports that prosecutors were investigating him "irresponsible" and "thinly sourced." Thursday, the 31-year Senate veteran issued a one-sentence statement: "I have and will continue to cooperate with any inquiry."

News of a grand jury looking at Skelos comes 12 weeks after a separate federal probe toppled the leader of the State Legislature's other house, shaking up Albany.

In January, Bharara accused then-Assembly Speaker Sheldon Silver (D-Manhattan) of using his position to secure $4 million in bribes disguised as legal fees. His colleagues forced Silver to step down as speaker, though he has retained his Assembly seat and pleaded not guilty. Bharara at the time said his office was investigating other politicians and advised the public to "stay tuned."

Bharara's office also is looking into a payment to Adam Skelos for as much as $20,000 by American Land Services, a title insurance firm for which he never worked, the Times said. American Land Services is based in Syosset; its chief operating officer, Thomas K. Dwyer, did not return calls and emails seeking comment.

Adam Skelos is a vice president at East Coast Abstract, a Garden City-based title insurance company, according to its website. Approached at his Rockville Centre home Thursday, he directed questions to his attorney, who didn't return several messages.

County contract documents show AbTech was awarded a personal services agreement with Nassau's public works department based on a ranking assigned by county officials. The firm submitted a higher cost estimate than one of the other two bidders, but the county deemed AbTech the most-qualified firm based on "professional judgment."

advertisement | advertise on newsday

Brian Nevin, spokesman for Mangano, said the "county has been cooperating with law enforcement officials who have requested information relating to contracts that were awarded under an open, competitive and transparent" process.

Dean Skelos earns outside income as an attorney with Ruskin Moscou Faltischek, a Uniondale-based law firm. A spokeswoman for the firm said Thursday: "The firm was subpoenaed months ago and, since then, it has been fully cooperating with the investigation."

With Robert Brodsky,

Anthony M. DeStefano,

Robert E. Kessler, William Murphy and Darran Simon