Zander came from a rich family who owns citrus groves, a large ranch, and a business that Dexter says: "[dumps] phosphates in Lake Okeechobee." To the public he is a philanthropist who employs the homeless at the ranch, but in reality, he kills them and disposes the bodies in hydrochloric acid and keeps a single shoe as a trophy. He has connections to the cult of Moloch. It is believed he had killed more than two or three people.
Upon further investigation of Macauley's activities, Dexter discovered his favorite charity was One World Mission of Divine Light. It was probably the charity he used as facade to lure his victims.
Dexter planned to investigate Zander's yacht, however as the boat was parked on the Royal Bay Yacht Club, and as stated by Dexter, the security there was too high, he was unable to search there for evidence of Zander's murderous hobbie.
Dexter kills him the same way Zander killed his victims, and even thinks about taking a shoe as a trophy.
Mentioned on files found by Dexter, though not confirmed as deceased, they were taken by Zander and were never heard of again.