After reports that a cougar was seen roaming Microsoft's campus, the Washington Department of Fish and Wildlife searched the company's Redmond campus with hunting dogs on Sunday.

The dogs searched the campus for two to three hours but were unable to find anything.

"I’m highly suspicious and there could very well be a cougar there," said Capt. Bill Hebner ofFish and Wildlife. "If we get a fresh report, we’ll be ready to respond with those hounds again."

Cougar reports popped up on Thursday, Friday and Saturday. On Thursday, Microsoft security received a report of a cougar behind Building 32, according to Redmond police. In the afternoon, security guards saw a coyote near Building 30.

On Friday, Redmond police heard from Microsoft security -- again a cougar sighting on campus.Fish and Wildlife also received a report from Microsoft after the company security guards found a pile of scat that could have come from a cougar.

On Saturday afternoon, the state department received another report of a cougar sighting, which prompted the hunting-dog search. The department is asking anyone who sees a cougar to call 425-775-1311.

Jim Bove, spokesman of the Redmond Police Department, said some Microsoft employees dressed up as tigers on Friday. He did not know whether the costumes were related to the cougar sightings.

Here is our earlier report from Thursday.