Some New York City police officers have been stopping people for questioning but not documenting the encounters as required, calling into doubt the official accounting of a significant decline in stop-and-frisk activity, according to the first report of the federal monitor overseeing the Police Department.

The finding is included in an 87-page report that was filed on Thursday morning in Federal District Court in Manhattan by the monitor, Peter L. Zimroth, who was assigned to carry out the court’s orders after its 2013 decision finding the department’s stop-and-frisk tactics to be unconstitutional.

The report also addresses new training and revisions to the policies that guide how stops are used, as well as the court’s call for greater involvement of supervisors in making sure stops are constitutional and free of racial bias, and the use of body cameras.

Mr. Zimroth, in a letter to Judge Analisa Torres filed along with the report, said that while “there is much to do,” he found that the Police Department was “moving in a positive direction.”