The Navy disclosed on Thursday that it has seen an increase in its personnel purchasing, using, and distributing the hallucinogenic drug LSD.
The Naval Criminal Investigative Service (NCIS) said it has "noticed an increase of drug investigations involving Department of Navy personnel" buying and using LSD during the past year.
"Many of these investigations involve purchasing the drug on the dark web," the NCIS said.
The drug appears to be making a comeback after being used rarely within the Navy from at least 2003 to 2006 when there were only four detected instances of staff taking the drug.
"Anyone with information relating to DON personnel buying or selling LSD or illicit substances either on or off the dark web should report it to NCIS," the agency said.
The NCIS also warned Navy personnel against purchasing LSD and other illegal drugs via online marketplaces run as part of the so-called dark web.
Drugs purchased over these networks are often laced with harmful substances, the NCIS said. In conjunction with other law enforcement agencies, the NCIS is working to police these online marketplaces as part of an effort to identify any Navy member who may be using them to purchase drugs.