The office of Marilyn Mosby, the state's attorney, will include the internal report as part of its own investigation into the death of Freddie Gray, who suffered spinal injuries sometime between his April 12 arrest for carrying a switchblade knife and his arrival at a police station.
Gray's death a week later has become the latest flashpoint in a national outcry over the treatment of African-Americans and other minority groups by a white-dominated US law enforcement establishment, Reuters reported.
After a night of rioting in Baltimore on Monday, protests spread to other major cities later in the week in a reprise of demonstrations last year set off by police killings of unarmed black men in Ferguson, Missouri, New York and elsewhere.
A few hundred protesters marched through Baltimore in a noisy but peaceful demonstration on Thursday, joined by NBA star Carmelo Anthony and other celebrities, ahead of a 10 p.m. EDT (0200 GMT) curfew that city officials said would continue through the weekend.
"I'm hoping that we will get justice," said Janai Peters, 22, who works at an area hospital. She said city prosecutors must act quickly to resolve the case. "My hopes aren't high, but I am hoping for something positive."
The Washington Post reported that police on Thursday night found the body of a man inside a semi-truck parked near a CVS pharmacy that was burned and looted during Monday's violence.
Baltimore police spokesman Sergeant Jarron Jackson told the Post that officials were investigating it as a suspicious death, but it did not appear to be connected with the unrest.
A rally of about 1,000 people in Philadelphia briefly turned tense as protesters tried to march onto a highway and were blocked by police.