Thiebaut is voicing his support as his office decides whether to seek the death penalty in the rape and murder of a teenage girl. The former Democratic lawmaker also wants to be appointed U.S. attorney for Colorado.
Troy Eid, appointed U.S. attorney by former President George Bush, resigned after President Barack Obama took office and an acting attorney was named.
The Colorado House has approved a measure that would eliminate the death penalty and use the money to solve cold cases. The Senate will consider the bill next.
As a lawmaker, Thiebaut opposed the death penalty. He said his personal objections wouldn't be an obstacle to pursing it when warranted.
"As a district attorney, I'm duty-bound to enforce the law as it is written, not as I wish it to be," Thiebaut said.