Here are the first few paragraphs of The Shadow over Innsmouth, by H. P. Lovecraft. This secret investigation is the proximate cause of the creation of P4 division of the ONI.
During the winter of 1927-28 officials of the Federal government made a strange and secret investigation of certain conditions in the ancient Massachusetts seaport of Innsmouth. The public first learned of it in February, when a vast series of raids and arrests occurred, followed by the deliberate burning and dynamiting - under suitable precautions - of an enormous number of crumbling, worm-eaten, and supposedly empty houses along the abandoned waterfront. Uninquiring souls let this occurrence pass as one of the major clashes in a spasmodic war on liquor.
Keener news-followers, however, wondered at the prodigious number of arrests, the abnormally large force of men used in making them, and the secrecy surrounding the disposal of the prisoners. No trials, or even definite charges were reported; nor were any of the captives seen thereafter in the regular gaols of the nation. There were vague statements about disease and concentration camps, and later about dispersal in various naval and military prisons, but nothing positive ever developed. Innsmouth itself was left almost depopulated, and it is even now only beginning to show signs of a sluggishly revived existence.
Complaints from many liberal organizations were met with long confidential discussions, and representatives were taken on trips to certain camps and prisons. As a result, these societies became surprisingly passive and reticent. Newspaper men were harder to manage, but seemed largely to cooperate with the government in the end. Only one paper - a tabloid always discounted because of its wild policy - mentioned the deep diving submarine that discharged torpedoes downward in the marine abyss just beyond Devil Reef. That item, gathered by chance in a haunt of sailors, seemed indeed rather far-fetched; since the low, black reef lay a full mile and a half out from Innsmouth Harbour.
People around the country and in the nearby towns muttered a great deal among themselves, but said very little to the outer world. They had talked about dying and half-deserted Innsmouth for nearly a century, and nothing new could be wilder or more hideous than what they had whispered and hinted at years before. Many things had taught them secretiveness, and there was no need to exert pressure on them. Besides, they really knew little; for wide salt marshes, desolate and unpeopled, kept neighbors off from Innsmouth on the landward side.