(CNN) Two former sheriff's deputies who had been charged with involuntary manslaughter in the death of a college student in a Savannah, Georgia, jail early this year have been found guilty of lesser charges.

Former Chatham County Sheriff's Deputy Jason Kenny, 31, and his former supervisor, Cpl. Maxine Evans, 56, were accused of killing 21-year-old Mathew Ajibade.

A jury on Friday found them not guilty on the involuntary manslaughter charges, but Kenny was convicted of cruelty to an inmate. Evans was convicted of perjury and public records fraud for falsifying a report.

A third defendant, Gregory Brown, who was the nurse at the jail the night of Ajibade's death, was convicted of making a false statement. Brown was acquitted of involuntary manslaughter on Tuesday.

A cousin of Ajibade said he was not surprised by the verdict.

"I knew that that same system that failed Mathew would not be the system that got him justice," Chris Oladapo said. "I had already warned my family not to expect anything. We expected nothing, and we got nothing."

The deliberations began after an eight-day trial in Savannah during which jurors saw graphic police surveillance video the night Ajibade was taken into custody.

The video from January 1 included a more-than-one-minute clip showing a sheriff's deputy using a stun gun on Ajibade multiple times near his groin while he was in his underwear, restrained and motionless in a chair.

Nine Chatham County deputies, including Evans and Kenny, were fired in May in connection with Ajibade's death.

Force was 'justified,' former lieutenant testified

JUST WATCHED Answers demanded in jail death of Matthew Ajibade Replay More Videos ... MUST WATCH Answers demanded in jail death of Matthew Ajibade 06:46

During the trial, jurors were shown video from cell surveillance footage in which Ajibade appears agitated and resists deputies.

The video shows him combative as he thrashes on the ground violently. The situation escalates after Ajibade wrests control of a stun gun being used by a female deputy. That's when video shows Ajibade struck in the head multiple times by kicks and punches from deputies. He's eventually hog-tied and dragged away, off camera, to an isolation cell just before midnight.

It's the last image of him alive.

Hours later, just after 1:30 a.m. on January 2, Ajibade was found unresponsive in a jail cell.

The family attorney has said the video shows officers went too far.

"There has been this philosophy of disrespect and then covering up for it," said family attorney Mark O'Mara, who also is a CNN legal analyst.

But in court last week, former Lt. Debra Johnson, one of the jail supervisors present on the night of the incident, testified that the video stood in favor of the officers.

"It appeared that he punched the subject because he had a weapon in his hand at the time," Johnson said during cross-examination after watching the video.

"Is that force justified?" Evans' defense attorney Bobby Phillips asked her.

"That force is considered to be justified, yes sir," Johnson answered.

Johnson was forced to retire for her role in the incident.

Three deputies were injured by Ajibade during the jail altercation, including a female sergeant who suffered a concussion and a broken nose, according to authorities.

Attorney: Girlfriend gave police Ajibade's medication

Family members claim Ajibade was a much-loved "geeky kid" who traveled to Savannah to study computer science. The 21-year-old was diagnosed with bipolar disorder three years ago and was having a medical emergency at the time of his arrest and confinement, the family's attorney said.

According to the autopsy report, Ajibade died from "blunt force trauma ... a combination of abrasions, lacerations, skin injuries about the head and some other areas of the body."

The county coroner ruled the death a homicide.

Ajibade was arrested on January 1 after Savannah police received a domestic disturbance call outside of a local gas station. Ajibade was holding his girlfriend under a blanket when police arrived, according to an incident report.

Once uncovered, the woman's face was found to be bruised and her nose bleeding, the report says, and Ajibade refused to release her when ordered to do so by police. When police tried to arrest him, the report says, he resisted in a "violent manner." He was accused of domestic violence, battery and obstruction of an officer.

His girlfriend tried to inform police of his mental health issues and "gave police a bottle of his medication," O'Mara said.

Defense attorney: 'My client was overcharged'

Officials said Ajibade had to be restrained once he was taken to the jail, and that this was when he injured the three officers. He was moved to an isolation cell because of his "dangerous behavior," a police news release said.

Deputies said they conducted welfare checks on Ajibade and on their second check, he was found nonresponsive, police said. He was given first aid by the jail's medical unit staff. Ajibade could not be revived despite CPR and attempts to restart his heart with a defibrillator, according to the news release.

During the trial, Evans' defense attorney told the jury it was not incumbent on his client alone to check on Ajibade in his cell.

"Everyone who was in the jail that night had the responsibility to check on him, not just Maxine," Phillips told CNN in a phone interview.

"The law says a deputy has to check, not a specific deputy or supervisor. My client was overcharged, no question. She did not intend to harm him."