Casey Kasem's Widow Allegedly Assaulted by Business Manager

Casey Kasem's widow is in the market for a new business manager ... 'cause her last one allegedly flew into a violent rage and threatened to kill her.

Law enforcement sources tell TMZ ... the incident went down around 10 AM last Friday in Jean Kasem's L.A. home. We're told her business manager, John Gressy, got furious because Jean was giving money to her daughter, Liberty Kasem.

Gressy's rampage allegedly included throwing dishes and a vase at Jean, and we're told she was struck at least once and needed to be taken to a hospital for minor injuries. He also allegedly threatened to kill Jean, her lawyer and Liberty ... who was in the home and called 911.

John locked himself in a room, but when police arrived they arrested him for felony criminal threats. We're told he could be hit with more charges -- such as assault and/or battery -- once the case is submitted to the L.A. County District Attorney.

Jean's rep, Edward Lozzi, tells us there's no truth to any rumors Gressy and Jean were in any kind of "intimate or personal relationship."

Jean, of course, now has this to deal with on top of her legal drama with Casey's kids. As we reported ... she's been locked in a nearly 4-year legal battle with the family over Casey's estate.

She had also alleged Casey's kids conspired to kill the radio legend for his money, but an investigation cleared them.