The Adams County district attorney decided Monday not to seek the death penalty against Brian Washington in the shooting death of Aurora police Detective Michael D. Thomas.

District Attorney Don Quick said Monday he consulted Aurora police and the Thomas family before making the decision.

"At the end of the day, it is my obligation to make the decision based on the evidence, the law and what course is the best choice to ensure that Mr. Washington is held accountable for the murder of Detective Thomas," Quick said in a statement.

Monday was the deadline for prosecutors to file a notice with the Adams County District Court to pursue the death penalty against Washington.

Washington, 27, is accused of walking up to Thomas' car on an Aurora street Sept. 20 and shooting him at point-blank range.

The murder of a police officer is one factor that can trigger the death penalty in Colorado.

"In applying all of the relevant factors in this case to Colorado's death penalty statute and procedures - it is my decision not to seek the death penalty," Quick's statement said.

Washington was not in court Monday because he was at the Colorado Mental Health Institute at Pueblo undergoing a sanity exam in a Denver assault case that occurred two days before the detective's murder.

Washington pleaded not guilty in January to first-degree murder of a police officer after deliberation and assorted other counts in the detective's slaying.

Todd L. Nelson, Washington's attorney, told Adams County District Judge C. Vincent Phelps on Monday that Washington plans to change his plea to not guilty by reason of insanity.