TULSA, Okla. — A law enforcement report showed several members of an Oklahoma sheriff’s department raised serious concerns years ago about the performance and training of a volunteer deputy now charged in the fatal shooting of a restrained suspect.

Lawyers for Eric Harris’ family on Friday released a Tulsa County Sheriff’s Office memo outlining an investigation into Robert Bates.

Bates said he confused his handgun for his stun gun during an April 2 sting and has pleaded not guilty to second-degree manslaughter in Harris’ death.

The 2009 report said Bates had inadequate training for a role as an advanced reserve deputy. He had joined the Sheriff’s Office less than a year earlier.

The report found that Bates received special treatment that included department leaders’ ignoring complaints about his performance.