The curfew was lifted after a high-level review of the situation by senior state officials.
However, prohibitory orders under section 144 CrPC would remain in force, sub-divisional police officer Dharmesh Kumar said.
Kumar said the situation was tense, but under control.
The curfew was clamped this morning after tension escalated following the gunning down of Singh at Katira Mohalla under Nawada police station, 71 kms from Patna.