Senate Majority Leader Dean Skelos and his son, Adam, are expected to be arrested next week on federal corruption charges, sources said.

Skelos (R-Rockville Centre), the state's most powerful Republican, has been under investigation by U.S. Attorney Preet Bharara about whether he exerted any influence in matters involving his son's business dealings. The New York Times first reported Friday that Skelos could be arrested as early as Monday. Multiple sources said they had expected it Friday.

Skelos could become the second state legislative house leader charged with corruption this year. In January, Bharara charged former Assembly Speaker Sheldon Silver (D-Manhattan) with pocketing $4 million in kickbacks disguised as legal fees. His colleagues forced Silver to resign as speaker, though he remains an assemblyman. Silver has pleaded not guilty.

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Reports that federal officials were eyeing the Senate leader first broke in January.

Investigators have been looking at a contract for AbTech, an Arizona-based environmental firm that won a $12 million storm-water contract with Nassau County in 2013, sources said. The firm, which did not submit the lowest bid for the contract, had employed Adam Skelos as a consultant. He introduced county public works employees to the company, Newsday previously reported.

Newsday also reported that Nassau County Executive Edward Mangano testified before a federal grand jury looking into the matter.

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Skelos said last week he wouldn't step down as majority leader, a post he has held since 2011, but said he was cooperating with the inquiry. It wasn't immediately clear what charges Skelos or his son would face.

Skelos didn't return calls Friday. His attorney didn't return messages for comment. Adam Skelos also did not return calls yesterday.

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." A spokesman for Mangano, a Republican, subsequently said prosecutors said the county executive wasn't a target in the investigation.

AbTech also issued a statement saying it wasn't a target -- but companies rarely are targeted, a former prosecutor said. Instead, investigators focus on individuals.

After news of the probe broke, Nassau acting District Attorney Madeline Singas said she would investigate Nassau's process for awarding contracts.

AbTech also has secured municipal contracts with the villages of Sag Harbor and Babylon.