CIUDAD JUAREZ, Mexico — Gunmen staged four attacks on police within a half-hour period, killing four officers in a Mexican border city overrun by drug violence, an official said Monday.
Authorities are investigating whether the attacks Sunday night were coordinated, municipal police spokesman Jaime Torres said.
More than 40 Ciudad Juarez police have been killed this year, many of them in attacks blamed on drug gangs trying to consolidate territory. Many officers have quit out of fear for their lives, often after their names have appeared on hit lists left in public.
Another such list naming 26 officers was found early Monday at a dog racing track near the bodies of four civilian men, Torres said. One of the four had been decapitated, and a Santa Claus hat had been placed on his head. A fifth man who survived was left bound and gagged next to the bodies.
In Sunday night's violence, two officers were killed at a guard house outside a hospital. Another policeman was killed and a policewoman was injured when gunmen opened fire on a neighborhood guard station. The fourth officer was shot and killed while sitting inside his patrol vehicle at a park alongside the Rio Grande.
Gunmen in a car also opened fire on a municipal police station across from the Chihuahua state government offices, but nobody was hurt.
Ciudad Juarez, across the border from El Paso, Texas, has been the worst-hit city in a surge of drug-gang homicides sweeping Mexico. More than 1,300 people have been killed in the city of 1.3 million this year.
Across Mexico, more than 5,300 people have died in gangland-style killings in 2008 _ more than double the number last year, according to government figures.
In a report Monday, the National Human Rights Commission said more than 1,800 people have been killed in gang violence in Chihuahua state, making it Mexico's deadliest state. Next came Sinaloa state with more than 850 killings this year and Baja California _ home to the violent border city of Tijuana _ with more than 530.
President Felipe Calderon has deployed more than 20,000 soldiers across Mexico to wrest back territory from powerful drug cartels responsible for most of the cocaine that enters the U.S. But violence has continued.