Obama officials gave Senate Intel Committee list of Russia documents before they could be destroyed
Sen. Mark Warner, the ranking Democrat on the Senate Intelligence Committee (C-SPAN)

The Obama administration left behind a trail of clues for the Senate Intelligence Committee in case President Donald Trump's team tried to destroy evidence related to the Russia probe.

Officials in the outgoing administration created a list of document serial numbers and distributed the index to senior members of the committee, which held its first hearings Thursday about possible collusion between the Trump campaign and Russia, reported NBC News.

A former Obama official revealed the list was created in early January, and he hand-delivered it to committee members.

The official said he and his colleagues wanted to make it harder for the Trump administration to "bury" the information by keeping the document numbers -- which were not classified -- locked in an intelligence committee safe.

Reporting intensified in the last weeks of the Obama administration about possible Trump campaign ties to Russia, as intelligence officials rushed to publicly reveal allegations of collusion head of the incoming administration.