Noreen Welch, 74, a computer science engineer who at the age of 60 changed careers and became an intellectual property lawyer, died Dec. 28 at Holy Cross Hospital in Silver Spring. She had complications from colon cancer.

Her husband, James Welch Jr., confirmed the death.

Dr. Welch retired from her computer science career in 1994 after 30 years as a computer specialist with Mitre Corp. in McLean and then with Computer Science Corp.

In 1998, she received a law degree from the University of Maryland, then became a patent lawyer with the law firms Zito in Washington; Stevens Davis Miller and Mosher, also of Washington; and then Cha and Reiter in Paramus, N.J., for which she worked online from her home in Silver Spring. She specialized in computer encryption and security and retired in 2010.

Noreen O’Hara Caggiano was born in Brooklyn, N.Y. She graduated from Brooklyn College in 1958 with dual majors in mathematics and physics. She received a master’s degree in computer science from the University of Maryland in 1974, a master’s degree in information systems from George Washington University in 1989 and a doctorate in management of science, technology and innovation from GWU in 1990.

She attended graduate school at night while working full time during the day and raising four children.

Survivors include her husband of 48 years, James S. Welch Jr. of Silver Spring; four children, Pamela Skinner of Bowie, Allyson Cain of Fairfax County, Noreen Welch of Clarksville and Dr. James N. Welch of Sacramento; and nine grandchildren.

— Bart Barnes