WASHINGTON >> The Justice Department’s inspector general found no evidence that the FBI attempted to place undercover agents or informants inside Donald Trump’s campaign in 2016 as agents investigated whether his associates conspired with Russia’s election interference operation, people familiar with a draft of the inspector general’s report said.

The determination by the inspector general, Michael E. Horowitz, is expected to be a key finding in his highly anticipated report due out on Dec. 9 examining aspects of the Russia investigation. The finding also contradicts some of the most inflammatory accusations hurled by Trump and his supporters, who alleged not only that FBI officials spied on the Trump campaign but also at one point that former President Barack Obama had ordered Trump’s phones tapped.

The startling accusation generated headlines but Trump never backed it up.

The finding is one of several by Horowitz that undercuts conservatives’ claims that the FBI acted improperly in investigating several Trump associates starting in 2016.

He also found that FBI leaders did not take politically motivated actions in pursuing a secret wiretap on a former Trump campaign adviser, Carter Page — eavesdropping that Trump’s allies have long decried as politically motivated.

But Horowitz will sharply criticize FBI leaders for their handling of the investigation in some ways, and he unearthed errors and omissions when FBI officials applied for the wiretap, according to people familiar with a draft of the report.

The draft contained a chart listing numerous mistakes in the process, one of the people said.

Horowitz’s mixed bag of conclusions is likely to give new ammunition to both Trump’s defenders and critics in the long-running partisan fight over the Russia investigation. Last week, Trump described the coming report in a phone interview with “Fox & Friends” as potentially “historic” and predicted “perhaps the biggest scandal in the history of our country.”

A spokeswoman for Horowitz declined to comment. The people familiar with the inquiry cautioned that the draft report was not final.

The New York Times has not reviewed the draft, which could include other significant findings.

Trump has long chafed at the Russia investigation, which overshadowed the first years of his presidency. Ultimately, the special counsel who took over the Russia inquiry, Robert Mueller, found insufficient evidence to charge any Trump associates with conspiring with Russia’s interference.