HILO, Hawai'i -- Hawai'i County Mayor Billy Kenoi acknowledged yesterday that his office is investigating "very serious" and possibly illegal abuse of Internet access on county computers.

Kenoi said the investigation goes back to January 2008 and includes the potentially illegal use of county computers for political activity, as well as other serious abuses.

"We are not going to tolerate this type of behavior," Kenoi said. "We anticipate action will be taken in the future" that could include employee termination and even prosecution.

The mayor did not know when the investigation will conclude. He declined to say what other kinds of Web sites employees may have inappropriately been accessing.

Kenoi disclosed the investigation after Hamakua Councilman Dominic Yagong, chairman of the Finance Committee, pushed the administration for copies of a computer-use report that county data systems officials told him had been forwarded to the mayor.

Yagong was looking into allegations from some county employees, who say abuse of the Internet during working hours is hurting workers' productivity and contributing to the spiraling cost of overtime.

Yagong said employees alerted him to the abuse of Internet privileges while he was conducting a survey of employees' ideas on how the county can save money during this economic downturn.

There are 906 computers attributed to county employees across the island, not counting those on a separate system for security reasons in the Police Department and Prosecuting Attorney's offices.

Offices with computers range from Civil Defense and Mass Transit, with seven computers each, to Public Works, with 217 computers.

The publicly funded Web logging software keeps a six-month record of URL history, Yagong said. All he wants is a report saying the percentage of visits to specific Web sites by county department, as a tool toward targeting waste and abuse, he added.

"If there was any illegal or abusive behaviors regarding Internet usage, six months of history is more than enough for disciplinary action, legal action or investigative conclusion," Yagong said in an April 10 letter to Kenoi.

"In other words, unauthorized and/or illegal usage has stopped dead in its tracks. Releasing the report would have zero bearing on any 'ongoing investigation' as you can't investigate illegal usage that has voluntarily and abruptly stopped cold."

Yagong said he asked for the information more than two and a half weeks ago. He said Corporation Counsel Lincoln Ashida may have advised against releasing the information because of an ongoing investigation.

"To deny review of this report on the premise of an ongoing investigation, with all due respect, doesn't make any sense whatsoever," Yagong said.

Kenoi said it makes sense not to release the report because some people may be called as witnesses and others may be disciplined or prosecuted. He said employee unions are not yet involved in the investigation.

"When we finish a full, fair and thorough investigation, we will at the appropriate time release the report," Kenoi said. "This is a very serious matter, and we are taking it very seriously."