AUSTIN—Travis County District Attorney Ronnie Earle on Friday announced he won’t seek re-election next year.

The 65-year-old Democrat was at the center of the criminal investigation of Republican former U.S. House Majority Leader Tom DeLay.

DeLay quit Congress last year.

Earle’s term has one year remaining, and his resignation will bring to an end to his three-decade reign in which he battled some of the biggest names in Texas politics.

Earle has been criticized by DeLay and other Republicans, who say some of his prosecutions of elected leaders are politically motivated.

"This is a no-brainer for him. He never had any intention of finishing off his revenge on Tom DeLay and is scared to death of being Nifong-ed while still in office,” DeLay spokeswoman Shannon Flaherty said in a statement, comparing Earle to the disgraced district attorney in the Duke lacrosse team rape case. "Good riddance to another corrupt DA."

But Earle points out that he prosecutes Democrats as well as Republicans.

DeLay and the Republican fundraisers who were indicted with him are still awaiting trial in Austin.

Earle also tried to prosecute U.S. Sen. Kay Bailey Hutchison in 1994, but he dropped the case during trial. Hutchison was acquitted of official misconduct and record tampering charges.

Some Democrats prosecuted by Earle and his Public Integrity Unit were former Texas House Speaker Gib Lewis, former Texas Attorney General Jim Mattox, former State Treasurer Warren Harding and former Texas Supreme Court Justice Don Yarbrough.