Reports spread through social media about the cupcakes baked with semen and fecal matter and handed out by students at Centennial High School.
School officials asked the Bakersfield Police Department to get involved in the investigation.
Police said Friday afternoon that more than one student was involved in what appears to be a hoax.
Suspect and witness statements indicate the cupcakes only contained household kitchen items. But, some of the ingredients were "foreign substances" for typical cupcakes, police said. The students used mayonnaise, barbecue sauce and soy sauce.
Most students who tried the cupcakes didn't like the taste and didn't consume the food. One student ate a full cupcake and stayed home the next day with digestive problems, police said.
Police said they contacted the families of everyone involved, and none of the families wanted any action beyond the administrative process through Centennial High School and the Kern High School District.
Anyone with additional information for the investigation is asked to call Detective Ted King at (661) 326-3857.