Detective Ed Troyer told KIRO 7 Eyewitness News that CrimeStoppers has received a lot of tips in the case. Troyer said he believes "this case is going to be solved by a tip" from the public.

Investigators have determined the robbers headed north into King County following the killing on Wednesday night. Troyer said detectives later found evidence from the robbery at the 277th Street exit off of State Route 167.

Troyer told KIRO 7 Eyewitness News reporter Kevin McCarty that the crime scene was "particularly brutal," saying the robbers pistol-whipped the 14-year-old son of murder victim Jim Saunders. At one point, one of the men held a gun to the head of Saunders' wife, saying he would give her five seconds to tell him where the family's hidden safe was located, then began counting, "five, four, three," but did not shoot. Investigators said the family had no hidden safe.

Edgewood Man Fatally Shot In Craigslist Ruse Couple Tied Up, Home Ransacked In Robbery How To Stay Safe When Selling Items Online

Investigators returned to the scene Thursday to interview victims and process more evidence at the home in Edgewood.

"We’re using forensics. We’re using technology. There isn’t anything we aren’t using to find these guys," Troyer said.

In Wednesday night's incident, three men and a woman came to the Edgewood home to look at a diamond ring the family was trying to sell on Craigslist.

After one of them showed cash to the homeowner, the four entered the home, police said. Once inside, they held the family at gunpoint and pistol-whipped a 14-year-old boy, police said. When the boy's father intervened, an attacker shot 43-year-old Jim Sanders in the head, police said.

The four are also believed responsible for another robbery in Lake Stevens.

CrimeStoppers of Tacoma and Pierce County is offering a reward for information leading to the arrest of the three men and one woman involved in this robbery.

Anyone with information should call 253-591-5959. Callers can remain anonymous.

Previous Stories: April 29, 2010: Edgewood Man Fatally Shot In Craigslist Ruse April 29, 2010: Police: Craigslist Ads Tied To 2 Home Invasions, One Deadly April 29, 2010: Couple Tied Up, Home Ransacked In Craigslist Ad Robbery April 29, 2010: How To Stay Safe When Selling Items Online