Adrian Carracedo-Vega is charged with first-degree murder for the Dec. 30 killing of Sachely Diaz outside an apartment complex in Federal Heights, Colorado.
Memo from district attorney's office suggests workload, lack of staff meant Federal Heights Police Department failed to properly investigate serious felony cases.
Investigators with the 17th Judicial District Attorney's Office found "significant problems" in the Federal Heights Police Department, DA Brian Mason said.