PORTLAND — Lee Crocker, the principal of Lyman Moore Middle School, is retiring.

Crocker, who has worked for the Portland school system for 37 years, sent out an e-mail to parents on Thursday announcing his decision.

School officials said they don’t expect to announce a decision on an interim principal or plans for a permanent replacement until next week.

Before moving to Lyman Moore, Crocker was assistant principal at Portland High School.