State officials say DNA played a key role in the arrest of Joseph James DeAngelo, the suspected Golden State Killer. 

Democratic Assemblyman Jim Cooper of Elk Grove says the state could solve more cold cases if DNA samples were taken from those arrested for certain misdemeanors.

"We have horrendous crimes that go on every day, there are evil people out there, and come home and your loved one has been murdered, and there's no witnesses, no video," Cooper told Insight host Beth Ruyak. "DNA will play a part in solving that crime and people have to realize that and we have got to drive the narrative on this, and right now the best interest of Californians is not being taken care of."

Cooper says when Proposition 47 passed in 2014, several felony crimes were reclassified as misdemeanors, which removed the ability to sample for DNA during those arrests. He says that resulted in about 400 fewer cold-case crimes being solved each year in California.

"Anyone arrested in California for a felony, upon arrest in county jail, they swab your cheek for DNA," Cooper says. "So what happened since then, since 2014, our cold case DNA hits have dropped by about 2000 per year. This is per the attorney general's office."

Cooper has authored two bills that would have required samples be taken from those arrested for the very misdemeanors that were formerly felonies prior to Prop. 47. Both died in committee.

He hopes the DNA aspect of the Golden State Killer arrest will bring attention to his efforts.