About Us

Richard David Klein, Esq. joined the Diamond Law Group in 2002 while attending Touro College Jacob D. Fuchsberg Law Center, in Huntington, New York at night. He was admitted to practice law in New York in 2007, concentrating on transactional real estate law, including representation of buyers, sellers, and lenders. He has personally mentored most of our paralegals and attorneys, some without any previous legal experience, to become experts in the field. Mr. Klein also created an industry-standard interactive website allowing all involved parties to the transaction to log-in and follow along as their important transaction progresses.

Outside of work, Mr. Klein enjoys spending time with his wife Sarah, and three children, Matthew, Zoey and Dylan. He is a lifelong fan of the New Jersey Devils, Mets and Jets. Richard is also currently the Pack 776 Committee Chair, former PTA Vice President of Unqua Elementary School and volunteers as a DEK Hockey Coach.

Jonathan P. Bellezza, Esq is a 2013 graduate of Touro College Jacob D. Fuchsberg Law Center, in Central Islip, New York. He was admitted to practice law in New York in 2014 and is the newest partner at the firm as of 2017. His drive, professionalism, and attention to detail allowed him to make partner after just four years of working at Diamond Law Group. Mr. Bellezza now has a staff of three paralegals working at his direction and concentrates on transactional real estate law, including representation of buyers, sellers, and lenders.  Outside of work Mr. Bellezza enjoys cooking, exercising and spending time with his wife and three children, Jonathan, Joseph and Juliana.

Received his Bachelors of Science/Bachelor of Arts Degree from Georgetown University in 1983 and his Juris Doctor Degree from St. John’s University School of Law in 1993, and is admitted to practice law in both the state of New York and New Jersey, as well as the United States District Court, District of New Jersey and the Southern and Eastern Districts of New York.

Upon graduation from law school, Mr. Castiglione became associated with the Law Offices of Euclid F. Maggiani in Manhasset, New York, which concentrated its practice in the areas of general corporate law, real estate law, representation of individuals and lending institutions in commercial and residential real estate transactions, foreclosures, and trusts and estate planning.

While at the Law Offices of Euclid F. Maggiani, Mr. Castiglione supervised all real estate transactions, business sales, and corporate matters. He is the chief supervisor of all bank transactions and is responsible for all closings and the liason between each lender and the mortgage broker. Presently, he serves as a member of Ticor Title Guarantee’s Advisory Board.

Mr. Castiglione is a member of the New York State Bar Association, New Jersey State Bar Association, Nassau County Bar Association, Columbian Lawyers Association and American Bar Association.

Zachary Geller joined the Diamond Law Group team in 2024 as one of Richard Klein’s paralegals. He assists with all aspects of the firm’s residential real estate transactions. Zack attended the Crane School of Music where he studied Music Performance and  Music Education. After college, Zack made the decision to shift careers to the legal field through the inspiration of his grandfather, a practicing attorney for 60+ years. Since then, Zack has made it his goal to pursue a career in law with the hopes of going to law school. During his free time, Zack loves to play music, cook, and hang out with his two dogs, Jax and Rosie.

Delia Young joined the Diamond Law Group team in 2015 as Richard Klein’s paralegal, assisting with all aspects of the firm’s residential real estate transactions. Delia earned her bachelor’s degree from Stony Brook University with a major in Psychology and a minor in Political Science before completing her paralegal certificate at Hofstra University. Outside the office, Delia enjoys traveling, staying active with CrossFit, and spending time at home with her fiancé, Ryan, their two cats, Henry and Pepper, and their Bernese Mountain dog, Frankie.

Jenna Katsock joined Diamond Law Group in August of 2024. She is a recent graduate from Suffolk University Law School, and prior to law school, she graduated from Western New England University in 2018 with a Bachelor’s degree in Criminal Justice and a minor in Computer Forensics. In her spare time she likes to do yoga, travel, and spend time with her family and friends.

Jessica Montana joined Diamond Law Group in April of 2025 as a paralegal in the real estate department. Jessica studied psychology at Hofstra University. After graduation, she continued her education at Hofstra through the paralegal studies program. In her spare time, she enjoys reading and spending time with her family and friends.

Sabrina Nietzschmann is a Trust & Estates Client Services Director at Diamond Law Group, where she works closely with clients throughout the estate planning process. She assists with the preparation of estate planning documents, trust funding, and ongoing client services, helping guide clients through each step of planning for their future. Sabrina takes pride in providing compassionate, personalized service and making the estate planning process as smooth and comfortable as possible for clients and their families. Outside of work, Sabrina finds joy in watching beautiful sunsets and appreciating the little moments in life. She also loves spending time with her beloved cat, Han Solo.

Mitch is the Founder (retired) & General Counsel Emeritus of Diamond Law Group. Mr. Diamond has been practicing in the area of Residential Real Estate exclusively for 20 years.   His expertise has evolved over the past two decades through helping Buyers and Sellers navigate through their Home Purchases and Sales.   Coming from a restaurant background and integrating the same level of Customer service into the law business has led to his overwhelming success and popularity. Mitch also represents many of the Country’s most prominent Lenders.

Mitch is married with three children and loves to Travel and spend as much time as possible with his family.