LINCOLN CITY, Ore. - Police stormed a motel room in a seaside town Tuesday evening and captured a Washington state man suspected of killing his grandparents, ending a multistate search and a tense daylong standoff at the motel.

Officers found Michael Boysen lying on the floor on his back with apparently serious self-inflicted cuts, Lincoln City police Chief Keith Kilian said.

The 26-year-old was flown to Legacy Emanuel Medical Center in Portland.

Hospital spokeswoman Judy Pahl described his condition as critical shortly after he arrived late Tuesday night.

No officers were hurt in the standoff, which Kilian termed "very successful." Law enforcement officials in Washington state had described Boysen as extremely dangerous.

The bodies of Boysen's grandparents were found Saturday in their suburban Seattle home, a day after Boysen was released from prison and was greeted with a welcome home party. After those deaths were discovered, officials say they learned that Boysen had made threats against his relatives and law enforcement officials while behind bars.

Police spent much of Tuesday trying to persuade Boysen to surrender. After breaching the motel room door, they stormed in and captured him.

"We're certainly glad it's over and nobody else got hurt. We're glad they were able to take him into custody alive," King County Sheriff John Urquhart said in Seattle shortly after the capture.

During Tuesday's siege in the Oregon tourist town of Lincoln City, police pointed rifles at the motel, fired blasts from a water cannon to break the windows of Boysen's second-floor room and used a bullhorn to try to get him to give up. The Oregonian reports they also used tear gas.

Police used a robot equipped with a video camera and a microphone to communicate with him. The robot was sent onto a balcony outside the motel room. Police breached the door and were able to communicate with Boysen through the robot.

When Boysen didn't come out on his own, police went in after him.

"We tried to negotiate," Kilian said. "We saw an opening that didn't compromise the safety of our officers."

Boysen checked into the WestShore OceanFront Suites on Monday night under his own name but wasn't recognized until Tuesday morning, when a motel employee saw a television story about the case and called police, Kilian said.