Lt. Col. Alexander Vindman and his family are under 24-hour security monitoring after President Donald Trump and his allies have repeatedly attacked the impeachment witness on Twitter and during hearings, according to Forward.

Vindman requested that the Army conduct a security assessment, which included his family’s home and internet presence, and Army officials have said they are prepared to move Vindman to a military base if such a step becomes warranted.

A defense official told CNN on Tuesday that at present, there appears to be no need to move the family.

Trump has denounced Vindman on Twitter as a “Never Trumper,” and as he delivered his testimony this week, Vindman was cast by the official White House Twitter account as having questionable judgment.

Vindman testified “that he felt ‘there was no doubt’ that Trump was asking the Ukrainian president, Vladimir Zelensky, to investigate the Bidens in exchange for a state visit to the White House, which Vindman said Tuesday would bolster Zelensky’s political legitimacy in Ukraine and internationally,” Forward noted.