Maxine Kenny was found guilty of falsifying records. The nurse, Gregory Brown, was acquitted of manslaughter charges by the judge earlier in the week after an investigator admitted he had been indicted based on incorrect information about jailhouse policies.
The jury did find him guilty of perjury for claiming he had checked on Ajibade when security footage shows he never did.
Ajibade's cousin, Chris Oladapo told NBC News that he was not surprised the officers were found not guilty of the top charge.
"I knew that that same system that failed Mathew would not be the system that got him justice," he said. "I had already warned my family not to expect anything. We expected nothing, and we got nothing"
22-year-old Ajibade, a student, was handcuffed to a restraint chair in an isolation cell after he allegedly hit his girlfriend and broke a deputy's nose while in the midst of what his family described as a bipolar episode on New Year's Day.
Officers also placed a spit mask over his mouth. He was found dead in the chair, still wearing the spit mask, in the early morning hours of January 2.
Graphic video obtained by NBC News showed deputies tasing Ajibade in the groin while he was in a restraint chair — a controversial device that Amnesty International has said should be banned. The coroner ruled Ajibade's death a homicide, citing abrasions, scrapes and bumps on his upper body and head.