While there is no evidence that senior officials are reconsidering their stance that the crackdown was justified, the decision to detain and then release Dr. Jiang suggests that leaders are conflicted when handling high-level dissent on the issue. That may stimulate hopes that the party will sooner or later apologize for the violent suppression of the Tiananmen protesters.

''I think many people believe that detaining him was stupid,'' said a party official interviewed while Dr. Jiang was being held. ''On the one hand, he can't be allowed to criticize without punishment. But on the other, party elders do not allow their own people to be punished for nothing. He is elderly, he has a certain status and he did nothing wrong.''

The detention prompted sustained international criticism.

There was no official announcement of Dr. Jiang's detention on June 1, and the government has said nothing publicly about his release. Dr. Jiang's wife and children could not be reached for comment.

But it seems likely that the authorities will claim internally that Dr. Jiang showed remorse for his actions and, in Chinese party terminology, made progress in his political thinking under the instruction of military authorities.

While in custody Dr. Jiang wrote a ''thought report'' each day. By the end of his detention, Dr. Jiang had altered the report in a way that may allow his interrogators to claim that he admitted errors, the person informed about his case said.