BOSTON — Accused Boston Marathon bomber Dzhokhar Tsarnaev was badly injured when taken into custody in April, with multiple gunshot wounds, including one that had fractured his skull, according to court papers unsealed this week.

A trauma surgeon detailed the Chechen immigrant’s condition as Tsarnaev remained in a Boston hospital bed while charged with the bombing attacks that killed three people and wounded about 264.

Tsarnaev, now 20, had “multiple gunshot wounds,” Dr. Stephen Ray Odom of Beth Israel Medical Center testified on April 22, according to court papers unsealed Monday.

One shot that exited the suspect’s lower face was “the most severe,” causing a “skull-base fracture,” the doctor said.