Schoolchildren in the US state of Ohio were left bemused after images of nude women were shown in a politician's lecture on the legislative process.
Mr Barrett was elected in 2006
State representative Matthew Barrett was giving a computerised presentation at Norwalk High School when the images flashed up on the screen.
He said he had no idea where the images came from, adding that he took them down after a few seconds.
Mr Barrett was "embarrassed and apologetic", police said.
"I believe this was an unfortunate and unintended incident,'' Superintendent Wayne Babcanec told local media.
Mr Barrett, a Democrat elected to the state house of representatives last year, was giving a lecture on the US government.
He inserted a memory stick into his computer which he thought contained graphics showing how legislative bills became law.
Instead, a series of pictures of topless women appeared on the screen, although Mr Barrett said he shut down the computer within seconds.
He said several students chuckled when the images went up.
"It took me probably a second or so to look at it and say: 'That's not the Power Point,'" Ohio's Morning Journal newspaper quoted Mr Barrett as saying.
"It was extremely embarrassing and we had no clue that anything like that was on there."
School staff and police later examined the memory stick, which was found to contain a directory of nude images as well as the presentation.
Democrat spokesman Phil Saken said it had been a present to Mr Barrett from the state library.
It is not clear how or when the images were added.