The chairman of the House Judiciary Committee wants U.S. Attorney General Loretta Lynch to answer detailed questions about the 89 drug offenders to whom President Obama has granted clemency.

Rep. Bob Goodlatte, Virginia Republican, and 18 other committee Republicans say they are deeply concerned that Mr. Obama has been using his pardon power to benefit specific classes of offenders. They listed their concerns about the presidential pardons, which they say appear to be going to a vast number of federal drug offenders, in a letter Tuesday to Ms. Lynch.

The Committee oversees the Department of Justice, including the functions performed by the Office of the Pardon Attorney, and is now demanding answers about the pattern of the presidential pardons.

Earlier this week, Mr. Obama commuted the sentences of 46 men and women convicted of nonviolent drug crimes. He also commuted lengthy prison sentences for eight people convicted of drug offenses and issued pardons to 12 other federal convicts in December 2014.

From the surface, it looks as if the clemency initiative is a “plainly unconstitutional practice of picking and choosing which laws to enforce and which to change,” Mr. Goodlatte said in the letter. That initiative was established in April 2014 and calls on qualified federal inmates to petition the president for reduced or commuted prison sentences.

“This is not, as the Founders intended, an exercise of the power to provide for ‘exceptions in favour of unfortunate guilt,’ but instead the use of the pardon power to benefit an entire class of offenders who were duly convicted in a court of law – not to mention a blatant usurpation of the lawmaking authority of the Legislative branch,” he said.

Committee members are now asking Ms. Lynch to answer nine questions ranging from narcotics quantities to heroin trafficking. They have instructed her to respond to those questions no later than July 24.