A popular US national park will remain closed Monday as police hunt a gunman who shot and killed a federal ranger before fleeing into the forest, authorities said late Sunday.

A major manhunt launched immediately after the New Year's Day shooting in Mount Rainier National Park failed to find the suspect by nightfall, which hampered efforts to track him amid sub-zero temperatures.

Local media named the suspect as Benjamin Colton Barnes, 24, who allegedly killed 34-year-old park ranger Margaret Anderson after she set up a roadblock to corral the suspect who had sped away from an earlier traffic stop.

Barnes is reported to be a former soldier with previous run-ins with the law. He allegedly shot Anderson with a high-powered assault rifle before fleeing into the wilderness on foot at around 11:00 am local time.

Nighttime temperatures below 30 degrees Fahrenheit were expected as law enforcement officers search the expansive 368-square mile national park in Washington state, south of Seattle.

A car with weapons, body armor, and survivalist gear was discovered, although it was initially unclear if that car belonged to Barnes.

According to local media outlet KOMO News, Barnes is also believed to be connected to a shooting earlier Sunday that injured four in Skyway, a community approximately 10 miles southeast of Seattle.

Witnesses told the police that the suspect was asked to leave a party earlier in the night before returning and opening fire.

Law enforcement personnel have flooded the national park, centered on the spectacular snow-capped volcanic Mount Rainier, which is about 40 miles south of Skyway,

After the shooting, authorities focused on getting parkgoers out safely, some of whom are believed to be hunkered down for the night in lodges or other structures.

"We have been evacuating visitors but we do still have people in the park, there are people who are out snowshoeing or skiing who are coming back in," park spokeswoman Lee Taylor told CNN Sunday.

Taylor said about 85 visitors were being sheltered in the park visitors' center until it was safe for them to evacuate.

The park, which had only just opened for New Year's Day, was immediately closed after the shooting.

Calls to the office of the park's spokesman and Pierce County police were not returned. But an update on the park's Twitter feed late Sunday said simply: "The park will remain closed Monday, January 2nd, 2011."

A popular destination for hikers and outdoors enthusiasts, Mt. Rainier National Park boasts miles of hiking trails offering spectacular vistas of the 14,411-foot peak.

The incident has eerie similarities to the 1992 movie "Rambo: First Blood," in which Sylvester Stallone plays a troubled Vietnam Vet who evades capture outside the fictional town of Hope, Washington.