Investigators believe Garth M. Flaherty, 24, took as many as 1,500 undergarments from apartment complex laundry rooms before he was caught, police Cmdr. Chris Tennant said.
A man was seen taking underwear from two laundry rooms Saturday, a witness recorded his license number, and Flaherty was identified from photographs, Tennant said.
Police found enough underwear in his bedroom to fill five garbage bags, Tennant said.
"He said he had a problem," Tennant said.
Flaherty has been jailed on 12 counts of second-degree burglary and one of first-degree theft.
Police had previously received 12 reports of underwear thefts near Washington State University.
"We were kind of concerned about how to match up bras and panties with victims," Tennant said. "Based on the unique descriptions from a couple of women, we can tie him to those thefts."
The underwear will be held as evidence until the case is resolved, after which their disposition is uncertain, Tennant said.
"Would you really want them back?" he asked. "I would say not."