TULSA, Okla. — A 73-year-old Oklahoma reserve deputy who fatally shot a suspect who was pinned down by officers on Tuesday pleaded not guilty to a second-degree manslaughter charge.

Robert Bates declined to comment to reporters as he made his initial court appearance in Tulsa district court. His next court date is scheduled for July 2.

The Tulsa County volunteer has said he shot Eric Harris on April 2 after confusing his stun gun and handgun. The 44-year-old suspect died after running from a sting operation involving gun sales.

The district attorney charged Bates in the death after the sheriff’s office released video of shooting in which Bates is overheard apologizing for shooting the suspect.

In separate news conferences on Monday, the county sheriff and lawyers for Harris’ family disagreed on whether the reserve officer should have been allowed to conduct police work.

Sheriff Stanley Glanz said Bates, his longtime insurance agent and former campaign manager, had been properly trained and passed annual firearms certifications required by the state.

Dan Smolen, a lawyer for Harris’ family, said the Tulsa County Sheriff’s Office violated a number of its internal policies by letting Bates carry his personal handgun after training at the range on another weapon. Smolen also said the department failed to keep a permanent record of Bates’ training, in violation of local policies.

Records Bates released during the weekend showed that the volunteer officer was trained on a .45, not the weapon used in Harris’ death.

Bates, who sold his insurance business for $6 million in 1999, was trained to be a Tulsa Police Department patrolman in 1964 but left in 1965.

He was out of law enforcement for 35 years, returning for volunteer work in Florida in 2000 before joining the Tulsa County force in 2008 and making a number of donations to the agency. He also was Glanz’ campaign manager during the 2012 election.