Klaus Klausen Abo

Klaus Klausen Abo's parents were Klaus Klausen Abo in Soga om Sauda. His father was Klaus Sjursson Abo born 1726 and died 1797. His mother was Asgjerd Hallvardsdatter born 1723. His sibings were Siri b. 1750, Sjur b. 1755, Nils b.1756, Herborg b. 1762. One of the mail siblings, is supposed to have immigrated to Chicago and was a policeman there. He disappeared from apparently knowing too much information. Have just received a picture with Chicago printed on it and a male relative with a star badge on his jacket. It looks like the name is Clausen on the back but in pencil and faded, so hard to read. Am having trouble finding information, as to which sibling brother it would be. I know it's not Klaus himself who immigrated. Any help would be greatly appreciated. Thank you...