Manhunt continues for gunman who killed ranger at Mount Rainier National Park

(CBS/KIRO) MOUNT RANIER, Wash. - Police in Washington have launched a massive manhunt for a gunman who shot and killed a female park ranger in Mount Rainier National Park on Sunday.

According to CBS affiliate KIRO, police believe Margaret Anderson, 34, was shot when she tried to intercept a man after he failed to pull over at a routine traffic stop inside the park.

KIRO reports that authorities are now seeking Iraq War veteran Benjamin Colton Barnes, 24, for questioning in Anderson's death as well as a triple shooting in a Seattle suburb Sunday.

It reportedly took 90 minutes for help to reach Anderson after she'd been shot because the gunman kept firing at her backup before fleeing into the park.

Authorities told CNN that Colton, who they believe is heavily armed and wearing body armor, is still at-large in the park. The park has been closed to visitors since the shooting and the more than 100 people who had been kept inside the visitor center for fear the gunman might return, were finally escorted back to their cars early Monday morning.

According to court documents, Barnes was involved in a custody dispute over the summer, and his child's mother sought a temporary restraining order against him, reports KIRO. In an affidavit, the woman wrote that Barnes was suicidal and possibly suffered from PTSD after deploying to Iraq in 2007-2008. 

She said he gets easily irritated, angry and depressed and keeps an arsenal of weapons in his home.