In private negotiations in early March about a possible presidential interview, Mueller described Trump as a subject of his investigation into Russia’s interference in the 2016 election. Prosecutors view someone as a subject when that person has engaged in conduct that is under investigation but there is not sufficient evidence to bring charges.

The special counsel also told Trump’s lawyers that he is preparing a report about the president’s actions while in office and potential obstruction of justice, according to two people with knowledge of the conversations.

Mueller reiterated the need to interview Trump — both to understand whether he had any corrupt intent to thwart the Russia investigation and to complete this portion of his probe, the people said.