Gilgo Beach serial killer Rex Heuermann was disciplined for drug possession and smuggling a package into the infamous “Little Siberia” prison where he’s set to spend the remainder of his days.

Heuermann, 62, was caught by correctional officers in mid-July trying to smuggle something into prison, and was later found with unspecified drugs, according to disciplinary records obtained by The Post.

The twisted killer is currently locked in one of New York state’s oldest prisons, Clinton Correctional Facility in Dannemora, a bleak facility isolated in the frigid Adirondack Mountains near the Canadian border that’s now home to some of the nation’s most notorious murderers.

Rex Heuermann was caught by correctional officers in mid-July trying to smuggle something into prison, and was later disciplined for drug possession. Newsday

The records did not say what drugs he was caught with nor what was in the package he was attempting to smuggle into the prison.

A disciplinary hearing was scheduled Aug. 18 on the matter, according to prison records.

The former Manhattan architect admitted in April to killing and dumping the bodies of eight women along desolate stretches of Long Island, where their bound and partially dismembered bodies were found starting in December 2010.

In June, he was slapped with multiple life sentences as part of his plea, and is expected to participate in a “Mindhunter” style program with the FBI to help professionals figure out what makes his sick mind tick.

Heuermann is set to spend the remainder of his days Clinton Correctional Facility in Dannemora, New York. Getty Images

Heuermann’s murders went unsolved for over a decade until the investigation was reopened in 2022 and led to Heuermann’s arrest the next year — partly thanks to DNA from a pizza box he tossed in the trash.

All but one of his victims were mercilessly bound, tortured and strangled in a “kill room” in the basement of the family’s Massapequa Park home while his wife, Asa Ellerup, and their two children were out of town. 

Heuermann is now in “Little Siberia” with fellow Long Island serial killer Joel Rifkin and New York Zodiac killer Heriberto Seda behind the prison’s 60-foot-high, 7-foot-thick concrete walls.