Areview of medical records shows Brianna Grier suffered two separate skull fractures, on the back and side of her head, on the night she fell out of a moving police car in which cops failed to close the door, lawyers representing her family announced Monday.

And in an equally dramatic move, U.S. District Court Judge Lisa Godbey Wood rejected requests by the McMichaels — who were previously sentenced to life for their murder convictions in state court — that they be allowed to serve some part of the concurrent life sentences in federal prison.

The lawyer for Travis McMichael said that he had received hundreds of death threats and argued in court that her client would be safer in the federal system and less likely to be subject to “vigilante justice.”

But a number of Mr. Arbery’s family members came to court and argued that Mr. McMichael and the two other men convicted in the killing should receive no special treatment. Marcus Arbery, Mr. Arbery’s father, said that he wanted the men to “rot in the state prison.”

The sentencing hearings for Travis McMichael, 36, and his father Greg, 66, in a Brunswick, Ga., courtroom, were the first of three hearings set for Monday for the men, whose actions, caught on video, horrified the nation and the world. Prosecutors contended that the killing of Mr. Arbery was the men’s own version of vigilante justice, motivated by racism. The third convicted murderer who chased Mr. Arbery, William Bryan, has a hearing at 3 p.m. Eastern time.