During a yearlong string of shootings before his arrest in the summer of 1977, David Berkowitz, known as the Son of Sam, killed six people and wounded seven others in New York City.

Upon his confession to the shootings, the portrait of the serial killer that emerged was of a deeply disturbed loner, a man with a .44-caliber handgun who said he took orders from a demonic black Labrador retriever owned by a neighbor.

But in the years Mr. Berkowitz has been serving a 25-year-to-life sentence, he has been anything but alone. He has, it turns out, attracted an array of individuals from outside prison who, though they deplore his murderous past, have become friends, acquaintances and in some instances a kind of ad hoc set of assistants.

This circle of admirers, to a great degree, is made up of evangelical Christians, including a Town and Village Courts judge in upstate New York and a financial adviser in Manhattan, who have been moved by Mr. Berkowitz’s story of becoming a born-again Christian 23 years ago, and many of them have sought to publicize his account of redemption.