Town of Tonawanda police canceled a lockdown Thursday afternoon at Northtowns Academy, 333 Dexter Terrace.
Police issued the unconfirmed report of an armed student at the academy just before 3 p.m.
But the report turned out to be a false report, and police labeled it a hoax, according to Lt. Nick Bado during a press conference streamed live by WKBW-TV.
"All students are safe and accounted for," said Bado from a location near the school. "No one's safety was endangered."
Detectives were questioning a 17-year-old female in connection with the incident, said Capt. Joseph F. Carosi.
Tonawanda police detectives are investigating, police said.
"We will follow up on the false report," Bado said. "I don't know the details of how or who or what."
Bado noted a heavy SWAT presence around the school, an Erie 1 BOCES alternative high school.
"It's better to have more than not enough," Bado said.
Bus transportation for students was delayed, according to a post on the school's ERIE 1 BOCES website.
Dexter Terrace had been closed to vehicular traffic and pedestrian traffic at Niagara Falls Boulevard.
Parents were asked to assemble at 2065 Niagara Falls Blvd. in the Home Depot Plaza near the closed Walmart.
"It turned out to be a whole lot of nothing," said Carosi. "Ten years ago, no one would have heard about it, but today social media ran with an unconfirmed report."