BRISTOL, Conn.—The Episcopal Diocese of Connecticut is suing in an attempt to regain possession of a local church that broke ranks with the diocese over the appointment of an openly gay bishop.

The congregation of Trinity Episcopal Church in Bristol voted in May to join the more conservative Anglican Church of Nigeria.

The diocese’s lawsuit, filed this month in New Britain Superior Court, argues that Trinity’s rector, the Rev. Donald Helmandollar, and other church leaders gave up their legal rights to control the parish, its records and furnishings.

Connecticut Bishop Andrew Smith had ordered Trinity church members to vacate the buildings and surrender control of them to the diocese by July 8. Instead, church members said through an attorney that they would not give up the property and threatened to bring trespass charges against anyone from the diocese who tried to take it.

In May, the diocese also deposed Helmandollar—the equivalent of being defrocked—although he said he continued afterward to lead worship services in the church.