The Broadway producer behind the failed musical “Rebecca” was busted Tuesday for downloading child-porn — as disgusted neighbors said he once went around collecting signatures to get faster Internet.

“For nine years, he was not even able to say ‘hello,’ and suddenly he was quite friendly. … He needed to have his Internet,’’ a female resident said of accused kiddie-perv neighbor Ben Sprecher, 65, of Manhattan — who famously had his Broadhurst Theatre play “Rebecca: The Musical’’ torpedoed by a con man.

Sprecher — who has produced everything from Broadway’s “Brighton Beach Memoirs’’ to “American Buffalo,’’ as well as a national tour of “Little House on the Prairie’’ — is accused of downloading more than 100 videos and photos containing child pornography, according to court documents.

The sick stash included a nearly 46-minute video of a girl, described as between 10 and 12 years old, “engaging in various sex acts with an adult male,” the papers allege.

Sprecher shared at least four of the twisted files with an undercover agent over three days in June, the documents claim.

He has admitted to downloading the illicit porn, court papers say.

Sprecher was picked up by Homeland Security and the NYPD around 6 a.m. at his tony townhome on West 122nd Street in Morningside Heights, authorities said. His family was home at the time, according to law-enforcement sources.

“The police officers went inside the building, and they then brought him out. [Sprecher] had a smile on his face — probably nervous and embarrassed about what was going on,’’ said D.B. Shark, a Web-based radio host and local.

“He is a pleasant guy’’ Shark said. “This is so shocking. But you never know who’s next-door.’’

Sprecher allegedly amassed the online kiddie porn between at least October 2018 and this month.

Neighbors recalled how important the suspect’s Internet connection was to him a few years ago, with one resident, Jenny Raymond, saying he “made an effort to send out notifications [to get a faster speed] to all the neighbors’’ in 2014.

A Manhattan federal judge banned the producer from using the Internet at his arraignment Tuesday afternoon.

Sprecher’s public-defender lawyer, Martin Cohen, argued that his client needed at least his e-mail to work, to which the judge replied, “He doesn’t seem to be doing too much these days.”

Sprecher’s townhome is currently on the market for nearly $3.7 million.

Sprecher, who has been married for 25 years and has two adult children, also was barred by the judge from perusing any kind of porn and ordered “to avoid all unsupervised contact with minors.”

Prosecutors argued that he should be fitted with a monitoring device, too, but the judge refused.

Sprecher was released on $100,000 bond and ordered back to court Sept 12. His lawyer declined comment after the hearing.

In 2012, Sprecher and “Rebecca’’ co-producer Louise Forlenza were scammed by former Long Island stockbroker Mark Hotton, who netted $60,000 in fees from them with promises of lining up $4.5 million in investments for their psychological thriller.

Hotton then claimed one of his big investors died suddenly of malaria while on safari, and that KO’d the money pot. He pleaded guilty to money-laundering conspiracy and was sentenced to 34 months behind bars.

Then in 2017, Sprecher cried on the stand in Manhattan court while testifying against his former press agent, who he and Forlenza sued for $10 million, claiming the rep later scared away real investors who might have been able to save the production. The publicist was ordered to pay the pair $90,000.

Additional reporting by Kate Sheehy