They have to get rid of her body. They say they were in the light house area, because that's where the car may have been seen.
And no one knows where a text message is sent from...do they?
"So they were all three involved and Natalee died at Joran's house. Either drug overdose or struggle."
Personally, I don't buy the accidental OD (whether she was drugged or took them freely) bcse the logical thing for them to do then would be to either report it or toss her in the surf and drop her flip-flops on the beach with a towel, some drugs, and an empty bottle of booze. Then they could make up a story about consensual debauchery before leaving her on the beach, etc.
Assuming she's dead, they got rid of the body bcse they did something to it (bruised inner thighs, strangle marks, black eyes) that would've made an accidental death story impossible. I think she was killed during a struggle.
And I'm not convinced they were the only ones who harmed her.