Kevin Walsh, 62, a Washington private investigator since 1974, died of bladder cancer Dec. 28 at Washington Home and Community Hospice.

A friend, Mark Allen, confirmed his death.

Mr. Walsh was born in Woburn, Mass. He graduated from Northeastern University in Boston in 1974 and moved to Washington to work for Mark Lane’s Citizens Committee of Inquiry, which was pressing for a congressional reinvestigation of the assassination of President John F. Kennedy.

In 1976 and 1977, Mr. Walsh was a researcher for the House Select Committee on Assassinations. Later, he was a self-employed private investigator, and his inquiries included death penalty cases, voter fraud and the 2007 mass shooting at Virginia Tech.

He continued working until shortly before his death.

Survivors include a sister, Regina Walsh of Washington, and a brother, Alfred Walsh of Boston.

— Bart Barnes