TMZ Update: Demi Moore busts a move

LOS ANGELES (TMZ) - In today's TMZ Update, there's a criminal investigation underway in connection with the fatal attack involving Samantha Ronson's dog.

Officials from the County Department of Animal Care & Control tell TMZ there is a criminal investigation underway to determine cause of death for Tiger, the 3-pound Maltese that was killed after Sam's bulldog, Cadillac, got out of her apartment unit on Monday.

Plus, Sylvester Stallone allegedly ran a stop sign in L.A. yesterday -- and according to law enforcement sources, the actor was "less than cordial" during the traffic stop ... and ended up with a big, fat ticket.

TMZ was told a police officer watched as Sly failed to come to a complete standstill at a stop sign near the Bev Hills border ... then pulled the actor over -- and that's when things got rocky. According to sources, Sly vehemently "disagreed" with the officer's version of the events -- and was "less than cordial."

And finally, Demi Moore didn't just get up on stage at the Snoop Dogg show in Las Vegas this past weekend ... she got down and dirty! And in case you think her hubby Ashton Kutcher might be jealous -- he was right there, cheering her on!

Fore more details on any of these stories plus more, simply visit www.tmz.com .