In a sign that the bad old days have returned to Times Square, a sleazy Svengali sexually abused two teenagers he met on the Great White Way, plied them with drugs and alcohol and forced them to sell drugs on city streets, authorities said.

Shymell “Shy” Ephron, 35, allegedly supplied the 15- and 17-year-old girls with ecstasy, marijuana and alcohol, gave them a cellphone to monitor their whereabouts, and had sex with them every night for a week in May in his Harlem apartment, according to court documents filed by federal prosecutors in Manhattan.

FBI agents and NYPD police officers “rescued” the girls from Ephron’s clutches and now want to know whether other people were similarly mistreated, according to the United States Attorney’s Office for the Southern District of New York.

“There may be more victims of this alleged behavior,” authorities said.

“This is 100% reminiscent of the pimping and prostitution in Times Square in the ’70s, ’80s and early ’90s before Giuliani,” said retired NYPD Lieutenant John Macari.

“It’s a return to the bad old days,” he said, pointing the finger at smart politicians whose criminal justice reforms had emboldened the bad guys.

The case came at a time when Crossroads of the World was rocked by high-profile crimes, including the brutal attack on a tourist outside a four-star hotel in May and in February, when a young shoplifter shot a tourist in the leg in a store and then shot a police officer. In late May, a man was stabbed in both legs by three men believed to be armed with a machete outside a McDonald’s in Times Square.

Authorities did not provide details about the victims’ hometowns or backgrounds, nor would they comment on the scope of Ephron’s operation.

Ephron was arrested on July 10 and pleaded not guilty two days later to seven charges, including two counts of coercion and enticement of a minor. Each of those charges carries a minimum sentence of 10 years in prison, but the maximum sentence can be life in prison, court records show.

His release on bail was refused on the grounds that there was a risk of him fleeing.

Ephron has been arrested 15 times since 2009, on charges ranging from robbery to assault to drug possession with intent to sell, law enforcement sources said. In a “domestic” robbery on March 31, he allegedly stole an item from a woman’s apartment because she wouldn’t have sex with him, the sources said. He was arrested in connection with that incident on April 24 in Midtown.

“The NYPD needs to increase its patrols and undercover officers in this area. Criminals need to be uncomfortable with their uniforms and the possibility of their arrest,” said Michael Alcazar, a retired NYPD detective and adjunct professor at John Jay College, a former undercover officer who worked in Times Square from 1999 to 2006.

Alcazar said “increasing foot traffic, the refugee crisis, the impact of the defund-the-police movement and the central location of Times Square” are a recipe for “a resurgence of drug and prostitution problems.”

“It is a lucrative target for perverts who target delinquent teenagers,” he added.

“This office is committed to protecting New York City from sex offenders,” U.S. Attorney for the Southern District of New York Damian Williams said in a statement.

The FBI toll-free tip line can be reached at 1-800-CALL-FBI (225-5324) or https://tips.fbi.gov.