That evidence included the gun, bullets and shell casings, a videotaped interview, and police testimony that the suspect cried in his jail cell on the night of the deadly shooting.
Rollin Oliver, 21, is accused of shooting 32-year-old Celena Hollis, who was off duty but in uniform as she tried to break up a confrontation at City Park on the evening of June 24.
Oliver is charged with first-degree murder with extreme indifference. It's the best choice for Denver prosecutors to ensure a conviction, according to 9NEWS Legal Analyst Scott Robinson.
"Prosecutors need only show that Oliver shot into a crowd and didn't seem to care who might be killed," Robinson said.
There's a stack of evidence to help prove the prosecution's case.
Police found four shell casings 80 yards from Hollis' body, plus the bullet that killed the officer. The bullet was extracted from her head after she died.
The bullets and shell casings came from Oliver's gun, which police say was tucked in his waistband when he was arrested.
Bullets from Oliver's gun landed all over a packed City Park, including the ground and roof of a building.
Oliver admitted on tape to firing into the crowd, though he made conflicting statements about using one or both hands.
Police say Oliver cried in his cell the night he was booked.
"A young man can hardly be facing more serious charges, and charges that are difficult to defend against," Robinson said.
Robinson says police, prosecutors, and jurors always go harder when an officer's life is cut short.
"That is not to say that an ordinary citizen isn't just as important, but let's face it, the stops are pulled out when it's an officer who goes down," Robinson said.
What makes this case unusual, Robinson says, is that Hollis was never a target but simply the innocent victim of a single bullet.
"In some ways, that makes it even more tragic," Robinson said.
Oliver is being held without bond.
9NEWS reached out to his family but their lawyer has instructed them not to talk.
Court documents are expected to be released tomorrow detailing the evidence against Oliver.
His arraignment is scheduled for October 4th.
A number of people who appeared to be related to or know Oliver well were in court during his formal charging in July 2012. As he was taken away, they shouted phrases like "We love you, son" and "Keep your head up, pimp."
Jail records reviewed by the 9Wants To Know and The Denver Post show Oliver claimed he was a member of the Park Hill Bloods gang.
Oliver's public defender William Drexler says shots were fired as Oliver was leaving the park after suspected members of the Crips gang flashed gang signs.
He says Oliver had purchased a gun after he was shot at a party in an unrelated incident.
Investigators are urging eyewitnesses or anyone with information to contact Denver Metro Crime Stoppers at (720) 913-STOP . They particularly want any photos of the crowd.
(KUSA-TV © 2012 Multimedia Holdings Corporation with The Associated Press)