At least six Motel 6 locations in Washington state regularly shared information on their guests with Immigration Customs and Enforcement, a lawsuit filed Wednesday by Washington Attorney General Bob Ferguson alleges. In total, the facilities are accused of sharing the private information of more than 9,000 guests; six of those people were subsequently detained by ICE.

“This information was provided on an almost daily basis by some motels without the ICE agents having provided any documentation or evidence of reasonable suspicion, probable cause, or a search warrant for the requested guest registry information,” the lawsuit states. “Motel 6 was aware that the ICE agents used the guest registry information to identify and single out guests based on national origin, including guests with Latino-sounding names.”

Ferguson’s lawsuit was sparked by a September report in the Phoenix New Times that said two Phoenix-area Motel 6 facilities regularly shared information about their hotel guests with ICE. This practice reportedly led to the detention of at least 20 people there.

“That might be only the beginning. I’m sure this lawsuit is going to uncover more information that we don’t know,” said Jorge Barón, executive director of the Northwest Immigrant Rights Project. “So I certainly have real concerns that this actually [was] something that was happening at a national level.”

If ICE agents did target Motel 6 guests using their last names, they may have discriminated against people by national origin, which is illegal under Washington state law. That might enable an immigration lawyer to challenge the arrest, Barón explained.

In a statement, Motel 6 reiterated that it already asked its hotels to stop sending ICE information after the New Times’ initial report. Motel 6 also previously acknowledged that some of its Phoenix locations shared information with ICE, but said “this was undertaken at the local level without the knowledge of senior management.” “In September, Motel 6 issued a directive to every one of our more than 1,400 locations, making it clear that they are prohibited from voluntarily providing daily guest lists to Immigration and Customs Enforcement (ICE),” its Wednesday statement reads. “Motel 6 takes this matter very seriously, and we have and will continue to fully cooperate with the Office of the State Attorney General.”