Three people face federal charges of smuggling drugs into a Mat-Su state prison last year, with few details regarding the case yet released.

The defendants – Spencer Daniel Johnson, 24; Kalani Lemauga Maalona, 31; and Heaven Leigh Erick, 28 – are each charged with drug conspiracy, according to Acting U.S. Attorney for Alaska Bryan Schroder’s office. Johnson faces an additional charge of possession with the intent to distribute a controlled substance.

A statement from Schroder’s office says Johnson and Maalona were being held at the Goose Creek Correctional Center on April 8, 2016 when nearly 20 grams of heroin was passed to Johnson. Three days later, the drugs were seized by authorities.

Chloe Martin, a spokeswoman for Schroder’s office, said nothing further was available Friday regarding the defendants’ roles in the conspiracy or how the drugs were being smuggled into the prison. All three suspects are presently held on unrelated state charges.

The FBI investigated the case, along with the state Department of Corrections and Alaska State Troopers. If convicted, the defendants face up to 20 years in prison, as well as a fine of up to $1 million.

Adam Jason Spindler, who worked as a correctional officer at Goose Creek, accepted a plea deal last year after he was charged with smuggling drugs to inmates at the prison. Earlier this year, lawyer Kit Lee Karjala was accused of bringing drugs to Anchorage Jail inmates during attorney-client conferences.