We begin tonight with that breaking news, an arrest in what police are calling an assassination of a sheriff's deputy. He was simply filling up his patrol car during his shift when he was ambushed. It... See More
We begin tonight with that breaking news, an arrest in what police are calling an assassination of a sheriff's deputy. He was simply filling up his patrol car during his shift when he was ambushed. It happened at this Chevron station outside Houston. That deputy never even saw it coming. A shooter sneaking up behind him and opening fire. There he is, deputy Darren Goforth. A veteran officer, a husband and a father. And just a short time ago, the all-out manhunt leading to this man, seen on surveillance video. Tonight, he is already facing the death penalty. Authorities determined to see justice done. Leadings off tonight from Houston, here's ABC's kendis Gibson. Six to eight shots and an officer is down. Reporter: Tonight, authorities in Houston say they have captured the man seen here, suspected of gunning down a Houston area sheriff's deputy, execution style. We have identified the suspect responsible for this senseless and cowardly act. Today, the district attorney's office has accepted capital murder charges on Shannon J. Miles. Reporter: Authorities say 47-year-old deputy Darren Goforth never had time to react, shot in the back overnight while simply filling up his patrol car with gas. Suspect then continued over to him and shot the deputy again multiple times as he laid on the ground. Reporter: The veteran officer and father of two died at the scene. This is not an incident where an individual was provoked by a confrontation with an officer. This is just, you know, a cold-blooded execution. Reporter: His murder raising questions, whether anger over recent shootings by officers could have made his uniform a target. That does not mean that there should be open warfare declared on law enforcement. What happened last night is an assault on the very fabric of society. It is not anything that we can tolerate. Reporter: In Louisiana, three police officers shot and killed just this month. This year turning increasingly deadly for law enforcement officers. The number of police officers who have died while on duty rising sharply this year. 73 officer fatalities in 2014. So far this year, it's up to 82. We've heard black lives matter, all lives matter. Well, cops lives matter, too. So, why don't we just drop the qualifier and just say, lives matter? Reporter: Tonight, a growing memorial at the scene where deputy Goforth was gunned down. The steady stream of visitors feeling a sense of relief tonight, knowing there's been a quick arrest. Cecilia? Relief and still so much heartbreak there. Kendis, thank you.
This transcript has been automatically generated and may not be 100% accurate.