Update, Saturday 7:30 pm:

Authorities say they have a suspect in the Cascade Mall shooting in custody, but have not yet released other details. Follow the Washington State Patrol or the Skagit County Department of Emergency Management for updates.

The identities of the victims are also beginning to become public. The Seattle Times reports a Mount Vernon High School sophomore named Sarai Lara, 16, was the youngest of the victims.

Original post, updated Saturday 10 am:

Five people are dead after a shooting Friday night at the Cascade Mall in Burlington, north of Mount Vernon, according to the Washington State Patrol. Four of the victims, all women, were killed at the scene; one man died later at Harborview, according to the WSP.

Authorities have not yet found the shooter and do not know his motive, identity, or location. The WSP has released a photo of the suspected shooter and say he was last seen walking away from the mall toward I-5.

In a press conference this morning, Mount Vernon Police Lieutenant Chris Cammock, who's leading the multi-agency team investigating the shooting, said security footage shows that the shooter walked into the mall without a weapon and then entered the Macy's store at the mall ten minutes later with a rifle. Inside Macy's, he shot "four females ranging in age from teenagers to seniors" and one man, Cammock said. Cammock said the shooter appears to be in his "late teens or mid 20s." Authorities have not released the identities of the victims.

The shooter had left the scene by the time police arrived Friday night. They searched the 434,000-square-foot mall and evacuated employees and shoppers. Police recovered a rifle at the scene. Regional and state law enforcement agencies, as well as the FBI, are assisting local police in Burlington. The FBI said in a tweet it "has no information to suggest additional attacks planned in WA state" and is "Assisting with intel review & manpower."

Burlington Mayor Steve Sexton called the shooting a "senseless act. It was the world knocking on our doorstep and it came to our little community here."

Sexton offered support to law enforcement officers to "extend the long arm of the law to bring this son of a bitch to justice who did this to our community."

In a statement, Governor Jay Inslee offered condolences and prayers:

Tragedy has struck in Washington tonight. Our hearts are in Burlington where a shooter has taken the lives of at least four people. Many questions remain but our state patrol and local law enforcement are on the scene working swiftly to locate the shooter and clear the area.

Trudi and I send our condolences to the families of the victims and prayers for anyone injured. We urge residents to heed all safety and detour warnings. Stay close to your friends and loved ones as we await more information and, hopefully, news of the suspect's capture.

The Seattle Times reports that the incident is the sixth mass shooting in Washington this year, according to the Gun Violence Archive, which tracks shootings in which four or more people are killed or wounded.