A pair of thieves crept deep into the inner reaches of the UC Berkeley graduate school of journalism in the middle of the night, stealing about $25,000 worth of electronics, police said Wednesday.

The theft was at least the second at the journalism school in recent years, raising questions about security at North Gate Hall at the north end of campus.

Two prowlers were captured on surveillance footage in the July 17 break-in, said Sgt. Sabrina Reich, a spokeswoman for the campus police department. It happened sometime between 2:40 and 5:10 a.m., she said.

She declined to provide the footage, citing the ongoing investigation, but a source familiar with the probe provided The Chronicle a police flyer the journalism school was asked to circulate. The source asked not to be named, citing the ongoing investigation.

Reich said a preliminary investigation indicated burglars gained entry to the multistory school of journalism through a window that was left ajar.

She said she was “not sure” what happened inside. But the source familiar with the investigation said the two suspects forced open a dozen locked doors inside the building.

Reich said no one was injured in the incident, and it did not appear anyone other than the thieves was inside the building at the time.

Stolen, according to a flyer provided by the source, were multiple Apple computers and a high-end Sony camera worth $20,000.

Asked why the flyer was not circulated inside the journalism school, online or on campus, the source said that the school did not want to stereotype the thieves — who appear to both be African American males.

In a screenshot of the surveillance footage, both intruders were wearing hooded sweatshirts and appear to have taken some measures to conceal their identities. As of Wednesday afternoon, no arrests had been made.

The doors inside the building were broken open, the source said, to the point where they were barely hanging by the hinges and that some of the frames were splintered.

It “didn’t matter how much security and high-tech locks” the school had installed, the source said.

The source declined to comment on efforts made to improve security at the school in recent years.

It’s not the first time such a break-in has occurred at North Gate Hall. In November 2013, about $23,000 worth of computer equipment was stolen from North Gate Hall, the Daily Californian reported. It wasn’t immediately clear whether suspects were apprehended in that case.

Reich said that there were “no indications” that the theft was an inside job involving anyone at the journalism school or at the university at large.

Michael Bodley is a San Francisco Chronicle staff writer. Email: mbodley@sfchronicle.com. Twitter: @michael_bodley