Updated at 5:55 p.m.: Revised to reflect that Butch Groves has been suspended.

An Arlington private school has suspended one of its administrators over a Twitter message he sent to the attorney who represents porn actor Stormy Daniels.

Michael Avenatti tweeted a screenshot early Monday of the message, which was sent Sunday night.

In the message, Butch Groves, upper-school head of The Oakridge School in Arlington, calls Avenatti "a [expletive] douche bag" and a "lying piece of [expletive]." He has since deleted his account.

The school said Monday morning that it was "looking into" the incident and emphasized that the message was personal and not sent during work hours.

Monday afternoon, the school said it had suspended Groves indefinitely. He admitted sending the message and "deeply regrets his comment," head of school Jon Kellam said in a statement.

A tweet from Michael Avenatti, with screenshots of a message he received from Butch Groves. (Twitter)

"Oakridge employees are expected to maintain the respect, dignity and professionalism that is consistent with our mission," Kellam said. "Mr. Groves' conduct was unacceptable and inconsistent with these policies and standards."

Avenatti said earlier Monday that he hasn't had any other communication with the school or Groves, who he said "is not a role model for children."

The attorney, best known for representing Stormy Daniels, said he gets nasty messages on a regular basis, but that only "a small percentage rise to this degree."

Shortly before the message was sent, Avenatti had been tweeting about a client who he said had "credible information regarding Judge Kavanaugh and Mark Judge."

Kavanaugh, a Supreme Court nominee, has been accused of sexual misbehavior in high school and college, including an allegation that he sexually assaulted Christine Blasey Ford at a high school party while Judge watched.

Staff writer Tom Steele contributed to this report.