For decades, a man lived as Walter Lee Coffman, using his Social Security number, obtaining a driver’s license and passports, purchasing property and even cashing more than $100,000 in government retirement benefits, Justice Department officials said.

In reality, he was using the identity of another man who had been dead for close to 50 years, the authorities said, after going on the lam because he was facing attempted murder charges in Wyoming.

The run from the law ended last month, the authorities said, after multiple law enforcement agencies arrested the man, Stephen Craig Campbell, at his property in Weed, N.M. They charged him with misuse of a passport, officials announced on Wednesday.

The U.S. attorney’s office in New Mexico accused Mr. Campbell, 76, of assuming the identity of Mr. Coffman, a University of Arkansas graduate who died in 1975 when he was 22 years old.

University records show that Mr. Campbell and Mr. Coffman were both students at the university at the same time where they “pursued engineering degrees, suggesting a likely connection between the two,” according to the Justice Department.

Speaking to local news media in Arkansas, Mr. Coffman’s family said they were shocked to learn that his identity was stolen. Mr. Coffman’s aunt, Sharon Ennis, told 40/29 News that Mr. Campbell “desecrated” her nephew’s “good name.” She also shared that Mr. Coffman died in a car crash on his way home after visiting his fiancée.