Lindsay Lohan's father Michael Lohan is horrified by her wild nights out in Brazil and is concerned for her welfare.Michael Lohan has posted an open letter to the 26-year-old actress's booking agent Mike Heller, whose father is her lawyer Mark Heller, warning him that he will be held fully responsible if anything happens to Lindsay, who was reportedly spotted "out of it" in a Sao Paulo nightclub with her dress up around her waist and crying underneath a table.In the letter, posted on the Huffington Post, Michael wrote: "I am telling you now if you are with Lindsay in Rio or you booked it, and anything happens to my daughter, I am holding you personally responsible. Judging from what has happened to in the past, and the way she looks down there from the pictures in the media, it's not a good thing. If you have anything to do with her being there, its on you. Count on it. (sic)"The troubled starlet, who was sentenced to 90 days in rehab last week after pleading "no contest" to charges for lying to police about driving during a car crash last June, was photographed sitting on floor under the DJ booth with her dress pulled up on Thursday night (28.03.13), according to gossip website TMZ.com.The actress, who is in Brazil to promote a clothing line called John John Denim and was paid $100,000 to appear at the nightclub, was allegedly upset because of fans wanting to take her picture and hid under the table.She was also spotted partying again on Friday night and seemed in much better spirits.Meanwhile, Lindsay has been accused of stealing jewellery from the set of 'Anger Management' this week after going home with two bracelets, a necklace, sunglasses, a pair of shoes, gold earrings, a silk bathrobe, lingerie and tap shorts.But she claims she had a deal with producers that she could take whatever she wanted and they would deduct the cost of the items from her salary.