Lohan is said to have stolen 10k worth of clothing from Lauren Hastings, below, and to have threatened with Richie to destroy the items.

Lauren Hastings is a 22 year-old model who appeared in some Old Navy commercials and has been dating Nicole Richie’s ex, DJ AM. She was also a friend of Lindsay Lohan up until a short while ago, but it looks like Lindsay and Hastings had a falling out, and now Lindsay is chummy with Nicole Richie, who seems to be jealous of the new hottie that her ex is shagging.

Star Magazine is reporting that Lohan went over to Hastings’ house on April 15th and told a friend watching the house for Hastings, who was away working, that she needed to pick up some clothes she left there. Lohan absconded with $10k worth of designer clothes, purses and accessories, and had her security guard stuff it all into her car.

When Hastings got back, she was understandably upset and freaked out, and text messaged Lindsay to get her things back. Instead of owning up to the theft, Lohan said Hastings was making it all up, and showed the messages to her friends she was out with, including Nicole Richie.

Richie and Lohan laughed about it hysterically and threatened to destroy Hasting’s stolen items:

Lohan, whose normally chummy relationship with Lauren recently turned sour, scurried into her former pal’s bedroom, her bodyguard tagging along, and gathered up huge armfuls of clothes, purses and belts, a source tells Star. Almost everything was expensive, designer items, things Hastings picked up on various modeling shoots or bought at high-end designer stores. In all, the source says Lindsay and her bodyguard left with an estimated $10,000 in merchandise, which she ordered her security man to load into her car.

“The mutual friend saw Lindsay leaving with everything, but she just didn’t think that Lindsay would actually be lying about the clothes and steal their friend’s things! At the time, she was under the impression that Lindsay and Lauren were still friends! That is, until Lauren came home the following day and flipped out. She started yelling, ‘Where are all of my clothes? Where are my things?”…

“Lauren sent Lindsay a text message threatening to go to the police and press charges,” a source said.

Friends were out clubbing with Lindsay when she got the messages and at least one Lohan pal said the starlet responded by laughing uproariously. “Lindsay just told her she was delusional and claimed Lauren didn’t know what she was talking about. She insisted the items weren’t stolen because they did belong to her. Then she’d laughed to her friends about it. She thought the whole thing was hysterical,” a source said.

Lindsay was at the nightclub Hyde in L.A. at the time, sitting next to friends Nicole Richie and famed-DJ Samantha Ronson, and began passing around her Blackberry to show off the exchange, causing the girls to burst out in laughter.

Lindsay texted Lauren that she was a fat bitch, a friend of Lauren’s says. Nicole Richie also chimed in, a source said, and told Lauren that Lindsay would return the clothes after they cut them up!

“Nicole wrote that she and Lindsay were going to cut holes in Lauren’s jeans because Lauren was so fat and her jeans didn’t fit,” our source notes. “Then Nicole told Lauren that if she went to the cops, she would regret it!” our insider said.

Lohan is 20 and Richie is 25. Isn’t this even immature for teenagers? I love how the best insult they can come up with, even when they’re text messaging and have time to think of a clever one, is to call a fashion model “fat.”

When Nicole Richie was celebrating her birthday at the Young Hollywood party recently she asked security to block Hastings from entering her area. That was after this incident in which Richie told Hastings she would cut up all the clothes her buddy Lohan stole. No wonder she didn’t want to face her.

Hastings should call the cops and report the theft of her stuff. It would be delicious to see Lohan have to go to court.

Here’s a picture of Hastings, found at Evil Beet. The header picture of Lohan and Richie is an older one.