Josh and Susan Powell
Chris Detrick/The Salt Lake Tribune/AP; Amber Hardman/AP
08/25/2011 AT 08:00 PM EDT
About 20 detectives served a search warrant Thursday on the Washington state home of Joshua Powell, whose wife Susan disappeared
Joshua Powell, who has been identified as a person of interest in the case, was not detained. The couple's two sons were seen eating pizza in the backyard as the detectives from Utah and Washington searched the Puyallup, Wash., house.
"There will be no arrests today," the Pierce County, Wash., Sheriff's Office said on its Twitter page. "This is a evidence search warrant only."
The search comes amid signs the missing persons investigation is heating up.
Last weekend, investigators acting on what was called "important" and "credible" new information searched abandoned mine shafts
in Ely, Nev., about 230 miles southwest of where Susan Powell was last seen 20 months ago.
Joshua Powell initially told investigators he last saw his wife the night of Sunday, Dec. 6, 2009, at their then-home in West Valley City, Utah, southwest of Salt Lake City, when he took their sons for an overnight camping trip.
Joshua has since refused to talk to authorities and moved to Puyallup with the boys. He has suggested his wife ran off with another man.