Scotland Yard investigated a journalist trying to expose a plagiarism row and told him to stop asking a Cambridge professor questions.
Jack Grove, a reporter for Times Higher Education (THE), was accused of harassment after he emailed a series of questions to Prof Jason Arday about his academic record. Mr Grove said officers told him to stop contacting the professor because his “mental health” had been affected by the questions.
Prof Arday also hired the law firm Carter-Ruck, which suggested in a letter to THE that its “apparent attack” on him “may be… racially motivated”.
The Metropolitan Police spent four months looking into the claim of harassment before deciding in February to close the case.
The police did not interview Mr Grove, who only found out about the investigation when the Met contacted him to inform him that they would not be taking action.
The Met also reportedly passed on a complaint to another force about an academic who was also looking into the academic record of Prof Arday, but the other force refused to investigate.
The Met is among forces that have been accused in recent months of wasting time on pointless investigations while insisting that they do not have the manpower to routinely attend burglaries and other crimes.