WESTMINSTER, Colo. (CBS4) – Three students were arrested and several others are facing suspensions after marijuana edibles were found at a middle school in Adams County.

A full investigation is underway at Shaw Heights Middle School, near Westminster, after several students ate marijuana candies and later appeared high in class.

A total of 15 students were involved, according to officials. Four students are facing expulsions from the Adams 50/Westminster School District and 11 others are facing suspensions.

It started when teachers noticed a few students acting strangely during class.

“At least one of the kids had brought these products to the school and began sharing them with friends,” said district spokesman Steve Saunders.

Some students said they didn’t know there were given marijuana. According to the district, the candies are the size of a Tootsie Roll.

Marijuana, especially the edibles, has been a big topic of conversation at schools since recreational pot became legal. Adams 50 even launched an awareness campaign for parents and students.

“That parents need to talk to their kids about what is out there and what they could be coming in contact with,” said Saunders.

The district said the arrests and suspensions of the middle school students serve as a teachable moment for other kids and parents.

“You can’t put your head in the sand. This is an issue out there. Kids are going to be exposed to this,” said Saunders.

The Adams 50 School District says marijuana-related situations like this one are happening in many schools and that parents need to talk to their kids about it.