AUSTIN, Texas (CBSDFW.COM/AP) — The former Dallas County sheriff who’s now the Democratic nominee for governor says she has been a “responsible gun owner” as authorities continue searching for her on-duty firearm that is missing.

Lupe Valdez said Thursday she has done due diligence in looking for a 9mm Beretta that was reported as having not been returned after she left the department in December.

Valdez was Dallas sheriff for 13 years before stepping down to begin a longshot run against Republican Gov. Greg Abbott. She said in a statement that she believes the weapon was misplaced during that transition but didn’t elaborate.

Valdez says she has been entrusted with a weapon for more than 40 years and takes responsibility for “any error” that happened.

Dallas County authorities are investigating.

Here is Valdez’s full statement on the matter:

“I have been a responsible gun owner for over 40 years. Throughout my career in the military and law enforcement I have always followed departmental protocols to secure my weapons. During my transition from Sheriff to candidate in 2017, I followed protocol to return Sheriff issued property. Once I was notified that my weapon was not accounted for, I did my due diligence to locate the weapon. To my knowledge, my weapon was misplaced during the transition.

“I’ve been entrusted with a weapon for over 40 years. I’ve been entrusted to lead our men and women in uniform. As a leader, I take responsibility for any error that happened during my transition regarding my weapon. I take gun ownership seriously and I have cooperated with the department.

“I promise this: I will not stop talking about common sense gun reform and will not be strong armed by my opponent to silence the debate on gun violence and responsible ownership.”

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)