New twist in the Karen Read case … the judge just suspended an evidentiary hearing after voicing “grave concern” over new information from prosecutors.

A hearing in Read’s retrial was moving along normally Tuesday when suddenly Judge Beverly Cannone called for a recess.

The swift change happened on the heels of special prosecutor Hank Brennan moving to exclude testimony from two crash reconstruction experts who were involved in the federal investigation into her case.

Judge Cannone said the new info from prosecutors was not only concerning, but also “may have profound effects on this defense and defense counsel.”

The crash reconstruction experts testified as defense witnesses in Read’s first trial, when they told the jury O’Keefe’s injuries were inconsistent with being hit by a car.

In the first trial, Read’s defense team claimed the crash experts were NOT hired by her defense … but in Tuesday’s hearing, prosecutors told the court they had information the crash reconstruction firm billed Karen’s defense team $23,925.

Read’s attorney, Alan Jackson, was reportedly asked outside the courtroom if he paid crash experts to testify … and he denied it.

Karen’s first trial ended in a mistrial after a jury voted to acquit her on charges of second-degree murder and fleeing the scene of an accident … but split on vehicular manslaughter charges, deadlocking 9-3 in favor of conviction. She’s set for a retrial in April.