Three correctional officers from Stillwater and Oak Park Heights prisons have resigned since the killing of one of their colleagues this week.

Joseph Gomm, 45, of Blaine, was killed in an industry building at Stillwater on Wednesday. Edward Muhammad Johnson, 42, is accused of bludgeoning with a hammer and stabbing him, a source told the Star Tribune.

A spokeswoman for the state Department of Corrections said the reasons the three officers resigned won't be made public.

Late Friday, Gomm's family thanked his colleagues as well as others who offered "overwhelming love, kindness and support."

In a statement released by the Department of Corrections, the family said it was devastated "by the senseless and tragic loss."

"Our pain is indescribable, but we take comfort in knowing how many people loved Joe as much as we did," it added.

Johnson hasn't been charged with Gomm's death. He is serving a 29-year term for fatally stabbing his 22-year-old Bloomington housemate in 2002.

Gomm is the first corrections officer in Minnesota to be killed in the line of duty,