The Washington-state home day care identified as the source of an E. coli O157:H7 outbreak that led to three children being hospitalized and the death of 4-year-old Ronan Wilson earlier this year has had its license revoked by the state.

The Columbian reports that Dianne and Larry Fletch had operated the day care for more than 20 years; their license was suspended in April while the state proceeded with an investigation.

The Department of Early Learning sent Dianne Fletch a seven-page letter explaining its decision to revoke her license. The letter was dated May 21, but the state announced the revocation on Thursday after receiving confirmation from the Fletches that they had received the letter, which had been sent by registered mail.

Larry Fletch said he and his wife will appeal the decision.