Russian investigators believe a couple arrested for murder in the city of Krasnodar may have practiced cannibalism for nearly 20 years and hidden victims' remains in their freezer and saline-filled jars occasionally used to supply "frozen meat pieces" to soldiers at a nearby military academy.

Police detained Natalia Baksheev, 42, and her husband Dmitry Baksheev, 35, earlier this month after the discovery of a series of grisly selfies on a cell phone showed graphic images of dismembered body parts. In one photo published in Russia media, Dmitry Baksheev appears to pose with what Russia's interior ministry described as "different parts" of a human body in his mouth.

City workers spotted the apparently discarded cell phone lying in the street.

After their arrest, the pair confessed to eating as many as 30 people, some of whom may have been lured into the Baksheev's apartment via Russian online dating sites. Once there, investigators believe the couple drugged their victims before killing them.

The investigation is still ongoing and police have not yet confirmed many details of the case. Only Dmitry Baksheev has been charged with one count of murder so far. However, the case could turn out to be one of the deadliest of its kind in Russia and follows revelations earlier this year related to an 18-year reign of terror by a serial killer dubbed "the werewolf."

Mikhail Popkov, a former police officer, confessed in March to killing 82 people ages 17 to 38 between 1992 and 2010. He raped all of his victims. "In one life, I was an ordinary person. In my other life, I committed murders, which I carefully concealed from everyone, realizing this was a criminal offense," he said in trial testimony.

In the Baksheev case, one of the couple's neighbors, a former nurse, told the Moskovsky Komsomolets newspaper that Natalia Baksheev made and sold pies to supplement her income and would sometimes tell local cafe owners they were filled with "whatever's around."

According to investigators, husband and wife both at one time worked at the military academy, although in what capacity, and when, is not clear.