The Washington Post has obtained a police document that states another prisoner in the van that transported Freddie Gray after his arrest heard Gray "banging against the walls" of the car and suggested that Gray "was intentionally trying to injure himself."

According to the Post, the document was written by a Baltimore police officer, and offers an account of what could have happened inside the van, although there is no evidence at this time to confirm the prisoner's account. The Post obtained the document under the condition that the prisoner involved would remain anonymous. 

Gray died in police custody after sustaining a serious and mysterious spinal injury. Baltimore police have admitted that Gray should have received medical attention sooner than he did. An investigation by the Department of Justice into Gray's death is pending.

Almost immediately after the Post published their report, some called it into question, pointing out the suspicious timing of the leak and its reliance on an anonymous source. Chris Hayes, an MSNBC talk show host, shared the reservations of Jayne Miller, a local Baltimore reporter, on his Twitter account:

.@jemillerwbal says by the time the stop was made to pick up the second prisoner, Gray was already unresponsive.

— Christopher Hayes (@chrislhayes) April 30, 2015

Second prisoner is loaded *30 minutes* after Gray is first put in the van. Is only in the van w Gray for 5 min according to @jemillerwbal

— Christopher Hayes (@chrislhayes) April 30, 2015

.@jemillerwbal on WaPo story "It is inconsistent with what we have reported."

— Christopher Hayes (@chrislhayes) April 30, 2015

.@jaynemiller saying medical evidence not consistent w Freddie Gray being injured *before* he gets in the van. Also...

— Christopher Hayes (@chrislhayes) April 30, 2015

that medical evidence suggests a severe spinal cord injury that would be very difficult to sustain in absence of the force of moving car

— Christopher Hayes (@chrislhayes) April 30, 2015

We'll be updating this story with more information as it develops.