A man indicted for caught-on-video a knifepoint rape could be behind 17 other sex-assault robberies around Brooklyn, authorities said Wednesday.

Brooklyn Supreme Court Justice William Miller ordered Thomas Gallishaw held on $1 million bail after prosecutor Linda Weinman told the court he was suspected of descending on a rash of women across the borough.

“There is pattern, he approaches [his victims] from behind,” the prosecutor said. “He throws them to the ground, then he climbs on top of them and sexually assaults them.”

The 23-year-old appeared irate at the allegations, puffing out his cheeks and sighing loudly as Weinman said the NYPD were still investigating those cases.

Gallishaw pleaded “not guilty” Wednesday as he was arraigned on an indictment charging rape in other crimes, for allegedly attacking a woman and robbing her as she left a Bushwick laundromat on June 12 around 10:30 p.m.

Weinman said security footage caught Gallishaw wrapping his arm around the woman’s neck, brandishing a blade, and then “dragging” her into a nearby alleyway.

Following the alleged rape, he stole her phone — and was later nabbed by police who used the Find My iPhone app to locate him. Gallishaw was carrying a knife when he was arrested, officials said.

Earlier that evening, he allegedly tried and failed to attack another woman, throwing her to the ground and climbing on top of her as he held a knife. But her boyfriend intervened, and he ran away, officials said.

Gallishaw was out on parole for a New Jersey robbery when the rape took place. He faces up to life behind bars if convicted.