Why are the employees suspicious of Melinda in Speak?
Here you must be referring to the section entitled "Hard Labor," where Melinda is sentenced to spending Christmas vacation working at her mom's store. The employees are suspicious of Melinda precisely because she is the daughter of the owner. They are afraid that Melinda will observe their lackadaisical behavior and tattle on them. Nothing is further from the truth, however, in that Melinda only wants to goof off herself. Once the employees realize this, they are fine with Melinda being there in general and "helping" in the back in particular. Melinda says it this way:
Since I'm underage, Mom sticks me in the basement stockroom. I'm supposed to refold the shirts, sticking them with eleven pins. The other employees watch me like I'm a rat, like my mother has sent me to the basement to spy on them. I fold a few shirts, then kick back and take out a book. They relax. I am one of them. I don't want to be there either. (73)
I find a lot of irony here in that Melinda actually feels a sense of belonging with these disgruntled employees, but she doesn't realize it. The irony is that Melinda searches for the same sense of belonging at school through the entire novel, but she doesn't notice that she has found that very sense of belonging at her mother's store.