The vending machines at Green Hope High School have been broken into three times over the past month, school resource officer Brian Smith said.
"It takes about five seconds to get in there, and he's in and out within two or three minutes," said Smith, who has seen the bandit on surveillance video. "He goes right to the cash. He leaves the coins behind, but he goes right for the dollar bills."
Vending machines also have been hit at Apex High School, Cary High School, Cary Christian School, Millbrook High School and Athens Drive High School in recent weeks, authorities said.
"It's definitely a felony. It's breaking and entering," said Capt. Dave Wulff of the Cary Police Department.
The thieves usually pry open a door or window to get inside the schools.
One man is in all surveillance photos and videos, although a second man appears in some instances, authorities said. The thieves sometimes get nothing from the vending machines -- they even wound up buying a soda during one break-in at Green Hope -- but they sometimes get about $200 per machine, authorities said.
Police are looking at possible patterns to the crimes, such as the time of night or the day of the week when the break-ins are occurring, Wulff said, adding that he doesn't believe high school students are committing the break-ins.