The charges against Heuermann include three counts of first-degree murder and three counts of second-degree murder.
He pleaded not guilty to all the charges brought against him.
Heuermann is a New York City architect and the owner of RH Consultants & Associates, Inc.
Heuermann lived in Massapequa, a suburban town in Long Island, and commuted to his office in midtown Manhattan.
Heuermann graduated from Berner High School in Massapequa in 1981 and is married with two children.
The Gilgo Beach murder case began in 2010 when a body was discovered, leading to the finding of three more bodies in the area.
The victims' cause of death is still unknown, but there is speculation of a potential serial killer being involved.
Some believe there may be another suspect besides Heuermann.