The Secret Service and the presidential campaign of Donald Trump are increasing security for the candidate and his rallies after threatening letters were received by Trump family members and violent protests by leftists broke out at a string of several recent Trump rallies.

Donald Trump turns to face down the threat as Secret Service agents and Trump’s personal security rush to protect Trump from a leftist protester who jumped a barricade and reached the back of the stage at a rally in Dayton, Ohio March 12, 2016.

NBC News reported on Friday: Secret Service Tightens Trump’s Security Amidst New Threats

“The Secret Service is ramping up their presence around Donald Trump as the joint terrorism task force investigates a suspicious envelope with powder that was delivered to Trump’s son.”

The NBC report aired before it was revealed that Trump’s sister, federal appeals court judge Maryanne Trump Barry, had also been sent a threatening letter that was received Friday but did not contain any powder.

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NBC’s Katy Tur reported the Joint Terrorism Task Force is investigating a white powder letter sent to Eric Trump postmarked in Massachusetts demanding his father drop out of the race. Preliminary testing of the powder was negative but the letter reportedly said the next letter would ‘not be fake’.

Tur added the Secret Service and FBI are investigating Anonymous declaring ‘total war’ on Trump and publishing Trump’s Social Security number and other personal information.

The NBC report featured former Secret Service agent Dan Bongino commenting on the assets deployed to protect Trump, saying it tells him Trump faces a “grave threat.”

“You have counter-assault assets, you have counter-sniper assets, this says to me that this is a grave threat.”

ABC News reported Sunday night that the Trump campaign will be increasing security staffing at Trump’s rallies so that senior staff will not have to get involved in the stands as happened on Saturday in Tucson where the media accused campaign manager Corey Lewandowski of grabbing a protester by the collar. The Trump campaign issued a statement denying Lewandowski was the one who grabbed the protester.

Donald Trump’s campaign said today it is beefing up security, after a string of protests and violence at the Republican presidential candidate’s events. “We will be dedicating additional security resources to larger events in the future to prevent staff from having to intervene,” campaign spokeswoman Hope Hicks said in a statement to ABC News. The statement comes the day after an incident involving Trump campaign manager Corey Lewandowski at a campaign event in Tucson, Arizona, that was captured on video. During the incident Lewandowski appears to grab the collar of a protester at the same time as a member of Trump’s private security team. The protester and his companion had been escorted out earlier in the rally. It is unclear how they came back in. Despite what can be seen on multiple sources of video, Trump’s campaign said in a statement Saturday night that Lewandowski made no contact with the protester and Trump made no mention of any footage during an interview Sunday on “This Week.” “And, I will give him credit. Now he didn’t touch him,” Trump said, adding that security had been “lax” at the event, despite the presence of local police, Secret Service agents, and his own staff.

A video by a Black Tucson police officer, Brandon Tatum, who attended the Tucson rally as a civilian has gone viral as he spoke about how shocked he was at the violent, profane behavior of the anti-Trump protesters.

Tatum also spoke about how he was not mistreated by the Trump supporters at the rally which he said was contrary to what the media was reporting that Black people get thrown out of Trump rallies for no reason.

Tatum said he feared for his safety from the anti-Trump protesters, saying of them:

“These people are the most hateful, evil people I’ve ever seen. I could not believe what I saw.”