The robbery late Thursday in Edgewood ended with the shooting death of 43-year-old James Sanders.
Sheriff's deputies said Sanders had listed an expensive ring for sale on Craigslist and was expecting a potential buyer to stop by the house.
Three men and a woman arrived pretending to be interested in the ring, but once inside one of them pulled a gun and tied up the parents.
"It was horrible," said Tim Jorgenson, brother-in-law of the shooting victim. "It was the scariest thing my sister's every been through. She thought she was going to die. They kept threatening to shoot her in the back of the head."
Detectives believe Sanders was shot multiple times while trying to protect his teenage son, who may have tried to fight back against the robbers.
"He saw his son being hurt, because they started hitting his son, because his son jumped on the back, tried to protect his dad," said neighbor Kamille Papini. "And I think Jim responded to what they were doing to his son."
The intruders ransacked the home and drove off before deputies arrived.
Sanders died at the scene, and his son was treated for a head injury sustained when he was pistol-whipped by one of the robbers.
Lake Stevens Police Chief Randy Celori said there's no doubt in his mind that the people involved in the shooting death are likely the same people responsible for a similar robbery Sunday night.
Investigators said in that incident, two men arrived at a home in the 1200 block of 84th Ave. SE after responding to an ad on Craigslist selling a flat screen TV.
The two men were armed with guns and tied up the family before letting a woman and two other men inside. The group ransacked the house, making off with jewelry, electronics and cash.
Police said the victims in Lake Stevens appear to have been targeted solely because of the Craigslist advertisement.
One woman who was inside the Lake Stevens home at the time of the robbery said when she realized what the potential buyers were really up to, it was too late.
"And I've replayed it over and over again for three days in my head of what could have done that could have changed it," said the woman, who wished to remain anonymous.
The woman said the crooks tied them up and cleaned out the home in less than 10 minutes, taking electronics, jewelry and cash with them. The woman and her husband sat, zip-tied and helpless, while their their 6-month-old boy lay asleep in his crib upstairs.
Investigators are hoping to recover DNA samples from the plastic zip-tie style handcuffs the robbers used in Lake Stevens, but officials say detectives have other leads they are pursuing. The police chief is convinced the robbers will be caught.
"We're not going to stop until they do, so, yes, I am," he said.
Celori said investigators believe the robbers are from Pierce County, but he would not say what led detectives to that conclusion.
These sketches show the men wanted in the Lake Stevens robbery.
The man on the left was described as mixed race (Asian/African/American), 18 to 24 years old, 5 feet 10 inches tall, thin build, and had a tattoo on his neck. The man on the right was described as black, 18 to 24 years old, 5 feet 6 inches tall, with a goatee and a thin build.