NEW YORK — A group of US investors have amended their lawsuit against Rupert Murdoch's News Corp to include Britain's phone-hacking scandal as evidence of a nepotistic corporate culture "run amuck."

Two pension funds and New York-based Amalgamated Bank, which manages about $12 billion for institutional investors, accused Murdoch of "a long history of abuses" in their lawsuit, originally filed in March.

New allegations that a Murdoch-owned tabloid newspaper, News of the World, hacked the voicemail of a murdered girl and slain British soldiers led the plaintiffs to add fresh ammunition to their lawsuit this week.

"These revelations show a culture run amuck within News Corp and a board that provides no effective review or oversight," reads the amended suit, which was filed in the US state of Delaware.

"It is inconceivable that Murdoch and his fellow board members would not have been aware of the illicit news gathering practices."

The lawsuit was originally filed to challenge News Corp.'s $675-million acquisition of Shine, a television and film production company run by Murdoch's daughter Elisabeth.

The lawsuit denounced the deal as part of a pattern of "rampant nepotism," stating: "Throughout his tenure, Murdoch has treated News Corp like a family candy jar, which he raids whenever his appetite strikes."

Australian-born Murdoch, now a US citizen, has built News Corp. into a global media empire which spans newspapers, television and Hollywood movies and wields immense political influence.

The group shut down the News of the World, one of Britain's most powerful newspapers, this week in response to a slew of accusations involving phone tapping, payments to police and other questionable behavior in covering the news.