Rex Heuermann has been charged with the murders of three women in the Gilgo Beach case on Long Island.

Who is this man named as a suspect in one of the most intense serial killer hunts?

The lifelong Long Island resident is a seemingly successful architect.

Neighbors tell News 12 that the 59-year-old married father kept a relatively low profile in his Massapequa Park neighborhood.

He graduated from Berner High School in 1981. Actor Billy Baldwin, a classmate, even shared his shock on the arrest.

FURTHER COVERAGE: Gilgo Beach suspect charged with murder Neighbors react to shocking revelations

Court documents show how an arrest was made

The suspected serial killer graduated with a degree in architectural technology from the New York Institute of Technology before reportedly working his first internship at Greer Construction corporation in Freeport.

He started his own company, RH Consultants and Associates, in 1994 in Manhattan - with big-name clients, including Target, Nike, Catholic Charities and Cipriani, according to the company website.

The website also boasts of the team's more than two decades of experience working with the New York City Building Codes and all major city agencies.

State records show Heuermann's architecture license is in good standing.

LIVE BLOG: Updates on the case as they happen

In an older interview posted by Bonjour Realty that News 12 has permission to share, Heuermann appears jovial - kidding about the weather on a gloomy day similar to the day of his arrest.

He goes on to brag about his prowess trouble-shooting negotiations with the New York City Building Department on behalf of his high-profile clients.

A search of his financial records shows a trail of federal tax liens dating more than a decade - one of them for over $100,000.

Records show he married his first wife, Elizabeth, in 1990. They divorced, and he has since remarried. His daughter reportedly works at her father's firm.

WATCH: DOCUMENTARY AND BACKGROUND INFORMATION - Gilgo Beach: Unsolved