Cops probing last weekend’s $250,000 art theft at a late billionaire’s Hamptons mansion are keeping an eye on the help. 

Southampton Village police say they’re checking out cable guys and phone and air-conditioning repairmen who recently visited the $12 million waterfront summer home of ex-Bear Stearns bigwig Paul Hallingby Jr., who died in 2005. 

“Everybody’s a suspect right now, so we’re just cobbling through the information,” said Detective Sgt.  Herman Lamison. 

The FBI has been contacted but hasn’t officially joined the probe, a federal source said, since there is no proof that any of the art has been taken out of state. 

An incomplete list of the stolen art includes works by such well-regarded artists as Jean Dufy, Frederick McDuff, Jacques Martin-Ferrieres and Cecil Everly.