The state has agreed to pay $20,000 to settle a lawsuit involving the beating of a Halawa Correctional Facility inmate by three prison guards in 2009, an amount the plaintiff’s attorneys in the case say is exceedingly low.

Joseph Tui Jr. was being held on suicide watch in an isolation cell when he got in a dispute with correctional officers over a request for a mattress, according to a 2011 complaint filed against the Department of Public Safety. Video surveillance showed three guards repeatedly punching him and kicking and stepping on his head.

Attorneys for Tui said he suffered physical injuries and “severe emotional distress, including nightmares, flashbacks, lack of sleep, migraine headaches and panic attacks” as a result of the beating, according to a summary of the settlement provided by the state attorney general’s office.

Four years after Tui was beaten by guards, he beat to death his 76-year-old cellmate at the Oahu Community Correctional Center.

Tui was found guilty of manslaughter last month in that case and is facing a 20-year prison term. Two of the three court-appointed mental health experts said Tui suffers from schizoaffective disorder. A third examiner, however, said Tui suffered from an antisocial personality disorder and faked his mental illness.

The settlement is one of four new claims against the state inserted into House Bill 2279 on Tuesday, right before a joint House and Senate conference committee voted to approve the measure. The bill includes 21 claims against the state totaling $10.2 million.

The three officers involved in Tui’s 2009 beating, Darren Kaneaiakala, Puifatu Fiso Jr. and Allen Tevaga, were later fired. They pleaded guilty to third-degree assault.

Eric Seitz, who represented Tui in the settlement, said that the state got off easy and that the case could have been worth a quarter-million dollars. However, Seitz said his client instructed him to settle.

“I will tell you that the settlement is outrageously low,” said Seitz. “What happened to this guy was atrocious.”

Attorney Myles Breiner, who filed the original lawsuit against the state and for several years represented Tui, agreed.

“It sends a message that you can do these things with impunity — $20,000 amounts to impunity,” Breiner said.

He said Tui had a history of mental illness and drug abuse, and was abused as a child.

“He would latch on to an idea and keep repeating it over and over and over again,” said Breiner, suggesting that may have provoked the beating by the guards.

He said that Tui had spent a lot of time in solitary confinement, which likely contributed to the decline in his mental health.

“He was seriously mentally ill and our response was to arrest and incarcerate and isolate,” Breiner said. “Frankly, I’m not surprised he ended up killing someone.”

Toni Schwartz, a spokeswoman for the Department of Public Safety, declined to comment on the case. She also declined a request to release the video footage of the incident, saying it is part of current litigation.

Here are the three additional claims against the state added to HB 2279 last week.

>> A $162,500 settlement against the Department of Land and Natural Resources. An Australian woman who had traveled to Honolulu for her son’s wedding fell over a metal pedestal on the sidewalk of the Ala Wai Boat Harbor. A motorist had knocked over the sign pole and DLNR had failed to repair it. The woman fractured her hip and missed her son’s wedding.

The woman “will suffer lifelong limitation of motion and chronic pain,” according to a summary of the case provided by the attorney general’s office.

>> A $10,000 settlement against the Department of Education. A fired DOE employee claimed that she was discriminated against due to her national origin or race and that she was retaliated against for participating in unspecified protected activities, according to information from the attorney general’s office. The employee had been fired for misconduct by then-Superintendent Pat Hamamoto related to her dealings with two principals at Hana High School.

>> $11,942 to cover plaintiffs’ costs in the Nelson v. Hawaiian Homes Commission case. Hawaiian Homes beneficiaries, represented by the Native Hawaiian Legal Corp., sued the state for failing to adequately fund the Department of Hawaiian Home Lands. The Supreme Court ruled largely in favor of the plaintiffs. The $11,942 is to reimburse the Native Hawaiian Legal Corp. for expenses. The state is appealing the case.