Hackers break into water system network

An infected laptop PC gave hackers access to computer systems at a Harrisburg, Pa., water treatment plant earlier this month. The plant's systems were accessed in early October after an employee's laptop computer was compromised via the Internet and then used as an entry point to install a computer virus and spyware on the plant's computer system, according to a report by ABC News.

The incident is under investigation by the FBI, but no arrests have been made in the matter, said Special Agent Jerri Williams of the FBI's Philadelphia office. The attackers are believed to have been operating outside of the U.S.