The campaign to rally support for Donald Trump’s pick to head the Justice Department is growing, with former FBI Director Louis Freeh, who served under President Bill Clinton, now joining the effort.

In a letter to the Senate Judiciary Committee, Freeh offered his “strong recommendation” that Senators confirm their colleague Jeff Sessions, R-Ala., as the next attorney general, defending his record on civil rights, which has become a key concern for critics.

“I have known Jeff since 1989 when we worked together as prosecutors on one of the most important civil rights cases investigated and prosecuted by the United States Department of Justice,” Freeh wrote. “[I] have always been greatly impressed with his commitment to the rule of law, his fair and balanced prosecutorial judgment, and his personal dedication to protecting civil rights.”



What Jeff Sessions Has Said About Race and Civil Rights



After Sessions was announced as Trump’s pick for attorney general, top Democrats and some civil rights groups expressed concern over decades-old allegations that he made racist remarks when he was U.S. Attorney in Alabama. Others alleged -- under oath during his 1986 confirmation hearings for a federal judgeship -- that he once called a white civil rights lawyer a “disgrace to his race” and dubbed some efforts by the National Association for the Advancement of Colored People "un-American."

During the hearings, one lawyer who worked with Sessions claimed the lawmaker told him he thought the KKK was "OK until I found out they smoked pot." Sessions said the comment was a joke but apologized.

Under oath himself, Sessions also insisted he harbored no racial bias and said the allegations were either false or being taken out of context. He was nevertheless blocked from becoming a judge.

In his letter on Tuesday, Freeh pointed to Sessions’ work on the 1989 murders of a federal judge in Alabama and an NAACP official in Georgia.

“I was struck with Jeff’s fierce determination to solve these civil rights murders, which so gravely impacted the rule of law and the guarantee of civil rights in America,” Freeh wrote, noting that, “Jeff and his office were key decision-makers in formulating and implementing the investigative strategy which ultimately led to the arrest and conviction of Walter Moody for these murders.”

Meanwhile, a conservative judicial organization, the Judicial Crisis Network, has created an entire website devoted to pushing Sessions' confirmation.

“He is a world-class legal mind and a tough but fair lawyer with invaluable experience,” says the website, ConfirmSessions.com. “Known for his deep respect for the Constitution and adherence to the rule of law, Sen. Sessions has worked tirelessly to defend the civil rights and legal rights of all Americans.”

Democratic Party leaders, meanwhile, have called Sessions’ nomination “deeply troubling.”

“Over the course of his career, Senator Sessions used the power of the courts to discriminate against civil rights leaders, allegedly used racially charged language to disparage minorities, expressed support for the KKK and then tried to dismiss it as a joke, celebrated the gutting of the Voting Rights Act, opposed same-sex marriage, denied the constitutionality of Roe v. Wade, voted against greater access to healthcare for veterans, blocked the Paycheck Fairness Act, and voted against the reauthorization of the Violence Against Women Act," Democratic National Committee Interim Chair Donna Brazile said in a statement last month.

Freeh, who served as FBI director from 1993 to June 2001, expressed no such concerns, calling Sessions a “friend” who has had a “distinguished” career in public service.

“I believe that Jeff will be an outstanding Attorney General for the Nation,” Freeh said.

ABC News' Melina Delkic contributed to this report.