Oklahoma Commissioner of Labor Mark Costello was killed Sunday evening in Oklahoma City.

According to reports, Costello was stabbed to death at an Oklahoma City restaurant. Costello's son, Christian Costello, was taken into police custody.

>> UPDATE: Son allegedly stabs, kills Oklahoma labor commissioner

Sen. James Lankford released the following statement:

"My family is stunned and deeply grieved to hear of the tragic death of Labor Commissioner Mark Costello. Mark was passionate about our nation, conservative fiscal principles, and the people of our state. Mark was a friend, and as we grieve, we will also pray for his family as they deal with this unbelievable tragedy."

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Oklahoma Insurance Commissioner John Doak released the following statement:

"I am deeply saddened by the loss of my dear friend Mark Costello. He was a wonderful leader and public servant. This is a major loss to the state of Oklahoma and everyone who loved Mark. My thoughts and prayers go out to his beloved wife Cathy and their family."

This is a developing story and KOKI-TV is working to gather more information.