OMAHA, Neb. (AP) — The man convicted of first-degree murder in four 2013 shootings shortly after he was released from prison has filed another lawsuit accusing the state of failing to adequately treat his mental illness.

Nikko Jenkins is seeking $1.7 million in damages because he says his mental health deteriorated during more than two years in solitary confinement.

The 28-year-old Jenkins made some similar claims in two other handwritten lawsuits filed against officials earlier this year, but those cases were dismissed because of technical problems.

A spokesman for the Department of Correctional Services, James Foster, declined to comment on the lawsuit filed Tuesday.

Jenkins shot and killed four people in Omaha in a 10-day period in August 2013, and was convicted of four counts of first-degree murder in April.