Bob Koss, a GOP Minnesota Senate staffer, is out of a job after attacking Rep. John Kriesel's support for gay marriage.

Kriesel, a military veteran who lost both his legs in Iraq, was one of only four House Republicans who voted against sending a constitutional amendment limiting marriage to heterosexual couples to the voters on November 6.

A portion of Kriesel's emotional 2011 plea to colleagues is featured in a 30-second ad for the campaign working to defeat the measure.

(Related: Republican John Kriesel featured in ad opposing Minnesota gay marriage ban.)

Koss went after the outgoing Kriesel on Thursday in a series of Twitter messages.

“Just saw the @johnkriesel gay marriage ad,” Koss tweeted. “Really glad the RINO [Republican In Name Only] will be leaving the legislature. #mnleg & good riddance.”

“Thanks douchebag,” Kriesel responded. (This tweet has since been deleted.)

“Wow, so the piece of shit representative confirmed by long standing belief #mnleg”

“@BobKoss you can dish it out but you can't take it. Hahaha!”

“@johnkriesel Go ahead and play your veterans card to shreds as you've done. You're a self serving SOB and I pity you.”

“@BobKoss who's office are you borrowing in that picture? Why are you pretending to be important?” (A reference to Koss' Twitter photo, which shows him seated behind a Senate desk.)

“@johnkriesel Answer me first toy publicity loving SOB. And your supporters are as disgusting as you.”

Before deleting his Twitter account, Koss apologized for his comments.

Senate spokesman Steve Sviggum said Friday that Koss is no longer a Senate employee but would not say whether he had been fired. (A video report is embedded on this page. Visit our video library for more videos.)