Selena Gomez is convinced former boyfriend Justin Bieber needs a better class of entourage, a Hollywood Web site reported. Citing a source it did not name, HollywoodLife.com said Gomez was upset at the recent upheaval at Bieber's estate north of Los Angeles and placed the blame on the pals hanging around with the pop star. One of the gang, rapper Lil Za, was arrested by sheriff's deputies investigating the egging of the house next to Bieber. Lil Za was busted for drug possession, but received public support from 19-year-old Bieber. "Selena is livid that Justin is not taking her advice and letting Lil Za stay at his house even though he is nothing but a bad influence," the source said. "Selena supports Justin, but when it comes to this recent decision, she is furious. She just doesn't understand why Justin is doing this to himself." HollywoodLife.com said a reason for Bieber's recent antics could be that he still carries a torch for Gomez and has been acting out since their breakup. TMZ.com said Saturday another source reported Bieber had added a drug combination called "sizzrup" to his reported consumption of alcohol, marijuana and Xanax. Sizzrup consists "typically codeine and promethazine mixed with Sprite and a Jolly Rancher," TMZ said. The source told TMZ Bieber's associates have been urging him to consider a trip to rehab.