SOUTHPORT, Ind. -- Three teens were running an elaborate drug operation in an apartment on Indianapolis' south side that belongs to the parents of one of them, police said.

A concerned citizen tipped police off to the operation, which included marijuana, Xanax, Ecstasy and two handguns, 6News' Sarah Cornell reported.

Police said Joshua Luksic, 18, kept everything in his closet at the Lickridge Court apartment, unbeknownst to his parents. Luksic's twin brother, Joseph, and their friend, Brooke Biddle, 19, helped, police said.

"Typically, you don't have this elaborate of an operation with someone that age," said Indianapolis police Sgt. Paul Thompson. "Apparently, some individuals brought the pills in, traded them for marijuana, and he resold those pills to other individuals."

Police think people had been coming to the apartment to buy and sell drugs for at least a year. Some neighbors said they had no idea.

"We saw kids going in and out, but we just thought maybe they were friends hanging out," said neighbor Pam Finchum. "We didn't expect any drugs or anything."

The three teens were arrested Thursday night. Police said Joshua Luksic admitted that he sold drugs for extra income. Investigators said he bought the handguns on the street.

"He stated he would use that in order to defend the drugs that he had in his possession," Thompson said.

Each teen faces multiple charges that could be upgraded if police determine drugs were being sold at Southport High School.