Don Sanders, a former Senate lawyer who revealed the existence of a recording system in Richard Nixon's White House, died Sept. 26 in Missouri after a long battle with cancer. He was 69.

Mr. Sanders had returned to his home state in the 1980s after more than two decades of federal government service--as a lawyer for congressional committees, as an FBI agent and as an assistant secretary of defense under President Gerald Ford.

Mr. Sanders was the GOP staff lawyer on the Senate Watergate Committee who first asked then-presidential aide Alexander Butterfield whether there was a recording system in Nixon's White House.

After Butterfield confirmed that there was, Mr. Sanders said he rushed to tell Fred Thompson, the lead minority counsel and now a Republican senator from Tennessee.

"We both knew then it was important," Mr. Sanders recalled in a 1997 interview with the Associated Press.

Thompson asked Butterfield about the taping system during nationally televised hearings three days later.

"It was actually Don who discovered the existence of the White House taping system, but he was too unassuming to ever mention it," Thompson said after hearing of Mr. Sanders's death.

In 1997, Mr. Sanders, while battling cancer, tried to launch a national campaign to draft Thompson for the 2000 Republican presidential nomination. Thompson declined to enter the race.

Mr. Sanders was born in St. Louis, graduated from the University of Missouri-Columbia law school and then spent two years in the Marines. From 1956 to 1959, he was city attorney for Columbia.

From 1959 to 1969, Mr. Sanders was an FBI agent. In 1969, he started working as a lawyer for congressional committees.

After returning to Missouri, Mr. Sanders served as a commissioner in Boone County in 1989 and 1990, but he didn't seek reelection. He had a private law practice in Columbia until his death.