Kimberly Cheatle, the director of the Secret Service resigned from her job, according to an email she sent to staff, following the assassination attempt against former President Donald Trump. This comes as Cheatle has been facing massive criticism after the attack on Trump.

She had been facing growing calls to resign and several investigations into how the shooter was able to get so close to the Republican presidential nominee at an outdoor campaign rally in Pennsylvania.

"I take full responsibility for the security lapse," she said in the email to staff Tuesday. "In light of recent events, it is with a heavy heart that I have made the difficult decision to step down as your director," she wrote, according to AP.

Cheatle's decision comes at a crucial moment ahead of the Democratic National Convention and a hectic presidential campaign season; it was unlikely to cease the scrutiny of the long-troubled agency following the events of July 13.

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Politicians from both parties have promised continued investigation, along with an inspector general probe and an independent and bipartisan effort launched at President Joe Biden's behest that will keep the agency in the spotlight.

Cheatle resigned the day after testifying before a congressional committee and being grilled for hours about the security lapses by both Democrats and Republicans. She accepted full responsibility for the security failings and referred to the attempt on Trump's life as the Secret Service's "most significant operational failure" in decades. However, her refusal to provide concrete answers about the probe infuriated lawmakers.

Biden said in a statement that "we all know what happened that day can never happen again," and he said he'd appoint a new director soon, but he did not discuss a timeline.

The president said he was grateful to Cheatle for her decades of public service. "We especially thank her for answering the call to lead the Secret Service during our administration and we are grateful for her service to our family," Biden said.

(With inputs from agency)