A surveillance tape taken from Wayne Valley High School shows two hooded people walking around the second floor Wednesday morning and putting suspicious devices into lockers, authorities said.

The school was evacuated after four suspicious devices with fuses were found in the building, one day before final exams.

Bill Maer, a spokesman for the Passaic County Sheriff's Department, said the students on the tape were walking around before school and were seen putting the devices into two lockers.

He declined to give details about the time they were walking around or how many students had been questioned in connection with the devices. No one has been arrested.

Passaic County Prosecutor James Avigliano described the bundled sticks as "pyrotechnic devices," but not dynamite or fireworks.

The bundles were found in two lockers on the second floor of the high school, prompting an evacuation of about 1,400 students.

A student noticed the fuses hanging from a locker. The 5- to 6-inch long sticks were removed by a bomb squad and detonated in a safe area, causing "a fireball and huge amount of purplish-gray smoke," Wayne Police Chief Donald Stouthamer said.

Classes at the school, about 20 miles northwest of New York City, end for the summer on June 21. Final exams began Thursday as scheduled.