"My beautiful boy is gone," Berman wrote Sunday in an Instagram post, which included an undated photo of her and her son smiling for the camera as Berman embraces him.
"A drug dealer connected with him on Snapchat and gave him (fentanyl) laced Xanax or Percocet (toxicology will tell) and he overdosed in his room," the photo caption said. "They do this because it hooks people even more and is good for business but It causes overdose and the kids don't know what they are taking."
Sammy died Sunday afternoon after an "experimentation gone bad," she said, adding that he had had "the drugs delivered to the house." He was pronounced dead at the Santa Monica home despite the efforts of firefighter-paramedics who responded to the scene, authorities said.
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Berman said Sammy was a straight-A student who was preparing for college.
"Please watch your kids and WATCH SNAPCHAT especially," the distraught mother pleaded. "That's how they get them."
Her son's death is being investigated by the Santa Monica Police Department and the Los Angeles County coroner's office.
Anyone with information about the case is asked to contact Santa Monica police dispatch at (310) 458-8491 or Criminal Investigations Detective S. Pollnow at (310) 458-8455.