The shocking sick images taken just weeks before she was admitted to rehab for the second time, shows drugs-crazed 20-year-old wild child holding a KNIFE to a friend's throat at a party.

The pal is also pictured sliding another blade down the Mean Girls star's breast... as Lindsay slips her own knife into her mouth..

A source told NOTW: "These photos are very worrying. Lindsay is so out of control. She should not be left within a million miles of a knife. The states Lindsay gets herself into she is lucky to be alive."

The images were taken at a house party where Lindsay was publicly claiming she was reformed and sober after her first bout of rehab.

Now she is back in a Malibu clinic after driving her Mercedes into a tree, high on coke and booze.