Law enforcement has stepped up its efforts in Colorado following violent threats against state Supreme Court justices who disqualified Donald Trump from appearing on presidential primary ballots there, with the FBI now investigating.

The FBI is aware of the situation and working with local law enforcement, Vikki Migoya, a public affairs officer at the agencys Denver field office, told HuffPost in a statement Tuesday.

We will vigorously pursue investigations of any threat or use of violence committed by someone who uses extremist views to justify their actions regardless of motivation.

The Denver Police Department told CNN that law enforcement responded to one justices home Thursday over what appears to be a hoax report, but declined to elaborate due to security and privacy considerations.

The Colorado court had ruled earlier last week that Trump was ineligible to run for the White House again, citing a clause in the 14th Amendment barring from state or federal office anyone who took an oath to uphold the U.S. Constitution but then engaged in insurrection or rebellion against it.

Online threats targeting the judges surged after the ruling.

This ends when we kill these fkers, read a message on one pro-Trump forum, first reported by NBC News .

What do you call 7 justices from the Colorado Supreme Court at the bottom of the ocean? Another asked. A good start.

CNN , meanwhile, reported that a member of a pro-Trump website had posted, All f robed rats must f hang.

The normalization of this type of violent rhetoric and lack of remedial action by social media entities is cause for significant concern, Daniel J. Jones, the president of Advance Democracy, a nonpartisan and nonprofit organization that studies public opinion, told NBC News.

Trump himself has engaged in rhetoric leading to threats against people involved in the multiple court cases he faces, prompting judges to issue gag orders against him.