The Jefferson County Sheriff's Office arrested four people Tuesday after an ongoing drug investigation.

Ryan A. Voris, 20, of Madison, Christian A. Stewart, 19, of Commiskey and Tammy R. Stewart, 39, of Madison were detained on charges of possession of methamphetamine and visiting a common nuisance. A 16-year-old male was also arrested on the same charges.

Tammy Stewart was in a relationship with Ryan Moreland when he died of a synthetic drug overdose in 2011. She assisted the prosecutor's office during their investigation of Julie Marshall and her store, Needful Things, by swearing in an affidavit that she saw Moreland purchase synthetic drugs from Marshall's store the day before he died.

The four arrests occurred after a search of a Taft Drive apartment where officers located methamphetamine and paraphernalia associated with the use of the narcotic.

Tammy Stewart, Christian Stewart and Voris were transported to the Jefferson County Jail where they await their initial court appearance. The 16-year-old was taken to a juvenile detention facility.