The archdiocese learned Sept. 11 that Father David J. Ajemian checked himself out of a medical facility located outside Massachusetts where he has been staying for the past several months.

This action was taken against the wishes of his bishop, Cardinal Seán P. O’Malley and medical professionals, the archdiocese said in a statement. “Our understanding is that he plans initially to return to Massachusetts to the care of his family.”

“As a priest of the Archdiocese of Boston, Father Ajemian made a promise of obedience to his bishop when he was ordained in 2001. In the context of these vows and with his medical care a priority, Father Ajemian was instructed to remain at an out of state residential treatment facility indefinitely to receive the care he requires,” the archdiocese said.

“By his own actions, he has violated this mandate from his bishop. Therefore, he is Absent Without Permission. He is not authorized to function as a priest,” the archdiocese said. “We pray for Father Ajemian, for his family and for all those who are concerned about his health and well-being. We also pray for those who have been impacted by Father Ajemian’s actions.”

Father Ajemian pleaded guilty in April to disorderly conduct after admitting he sent letters and DVDs to NBC late-night television host Conan O’Brien. In one of the letters, he called himself one of O’Brien’s “most dangerous fans.”

The priest was arrested while trying to enter the NBC building in Manhattan for a taping of “Late Night With Conan O’Brien” despite being warned to stay away by the network’s security personnel.

“I recognize that what I did was disorderly and I’m glad the people of New York have accepted that,” Father Ajemian said as he left the court. “I plan to return to the Archdiocese of Boston and I hope to return to ministry duties.”

Judge Rita Mella ordered Ajemian to pay a $95 court charge and signed a two-year order of protection directing him to stay away from O’Brien.