Rep. James LankfordJames Paul LankfordAfter Florida school shooting, vows for change but no clear path forward GOP senator: 'The problem is not owning an AR-15' Sunday shows preview: Russian charges, Florida shooting dominate coverage MORE (R-Okla.) on Wednesday suggested Attorney General Eric HolderEric Himpton HolderPavlich: The claim Trump let the mentally ill get guns is a lie Pennsylvania Supreme Court releases new congressional map 36 people who could challenge Trump in 2020 MORE is not worthy of being the keynote speaker at a graduation ceremony for Oklahoma police cadets.

"It's incredibly ironic that our nation's 'top cop,' AG Holder, who is delinquent in producing thousands of subpoenaed documents to the House Oversight Committee, was chosen to come to Oklahoma City on Thursday to swear-in our newest police cadets," Lankford said.

Holder is scheduled to be the keynote speaker for the Oklahoma City Police Department's cadet graduation ceremony on April 24.

Lankford, who is running for the Senate, called Holder a poor choice given that the House voted the attorney general in contempt of Congress in 2012 over the "Fast and Furious" gun-running operation.

"Oklahoma City's newest law enforcement officers should treat their duties of faithfully protecting and serving our community with the honor and dignity of their positions, not like AG Holder's tactics of obfuscation and redirection of blame," Lankford said. "I do not think our state has ever asked a federal official who is currently in contempt of Congress to speak to our graduates."

Lankford suggested that Holder should be replaced with another speaker.

"Given his numerous questionable decisions, his unwillingness to cooperate with congressional investigations and his Justice Department's opacity under this president, he would not be my first choice to stand as this administration's example of justice, leadership and integrity," Lankford said.

Lankford is a candidate in the June 24 primary to replace retiring Sen. Tom Coburn (R-Okla.).

Recent polling has shown him with a large but shrinking lead over his main opponent, former Oklahoma House Speaker T.W. Shannon, who has snagged the endorsements of Tea Party favorites Sen. Ted Cruz (R-Texas) and 2008 vice presidential candidate Sarah Palin.