Colorado cinema gunman James Holmes has been found guilty of the first-degree murder of all 12 victims and will be eligible for the death penalty.
Jurors rejected his insanity defence and found him guilty of killing them with "extreme indifference".
He was also found guilty on dozens of counts of attempted first-degree murder.
Holmes, dressed in a blue shirt, showed no visible reaction as the verdicts were meticulously read out over the course of an hour.
Many of the relatives in court started to cry as the first guilty verdict was announced.
"As soon as you heard the first guilty, we knew all the dominoes were about to fall," said Tom Sullivan, whose son Alex died in the shooting.
The jurors took about 13 hours to reach their decision following nearly three months of often emotional testimony.
They will return to court on Wednesday to hear from more witnesses to decide whether Holmes will be executed or jailed for life without parole.
The death penalty is rarely used in Colorado and the arguments over his sentence are likely to last about a month.
His lawyers are expected to argue his life should be spared because of his mental illness.
The verdict brings an end to what has been a three-year wait for the victims and their families.
Holmes, 27, pleaded not guilty by reason of insanity to 165 counts stemming from the 20 July 2012 shooting massacre that left 12 people dead and 70 injured.
But the jury found him guilty of all the charges.
His lawyers had argued the former neuroscience student was delusional and suffering from schizophrenia when he opened fire inside the packed Aurora theatre during a midnight screening of the Batman film The Dark Knight Rises.
They said he was suffering from the delusion that killing others would increase his "self-worth".
Two psychiatrists hired by the defence testified that Holmes' severe mental illness prevented him from distinguishing right from wrong.
"When Mr Holmes stepped into that theatre ... he had lost touch with reality," defence attorney Daniel King said in his closing arguments.
But prosecutors rejected the defence's claim that Holmes was unable to know the difference between right and wrong.
Two court-appointed psychiatrists who interviewed Holmes from jail testified that they determined he suffered from mental illness but was legally sane.
District Attorney George Brauchler also pointed to Holmes' methodical planning of the attack as evidence that he knew what he was doing.
Holmes detailed in a notebook the pros and cons of carrying out a shooting at an airport versus a cinema.
He drew maps of the Aurora multiplex and noted that theatre nine was best suited for an attack because its layout allowed for the fewest number of potential "escapees".
The prosecution also said the elaborate maze of explosives Holmes rigged throughout his apartment to stall police during the shooting showed that he understand his actions had consequences.
In his closing arguments, Mr Brauchler urged the jury to "reject this claim that he couldn't form the intent to murder".
He added: "That guy was sane beyond a reasonable doubt and he needs to be held accountable for what he did."
Jurors heard testimony from more than 250 witnesses, including dozens of survivors of the shooting, during the three-month trial.
Holmes did not testify.
Families of the dead said they were satisfied with the verdicts.
Eric Sullivan, whose son Alex was murdered in the attack, said: "I hope this guy no longer gets to breathe the sweet air Coloradans get to breathe."
Lonnie and Sandy James, parents of Jessica Ghawi, said they hoped jurors would now "do the right thing" and make sure "this animal, this monster, never sees the light of day".
Marcus Weaver, who saw his friend Rebecca Wingo killed, said he supported calls to execute Holmes.
"For a person who is anti-death penalty, I totally agree, I feel the sentence that he may get, which is the death penalty, is the only penalty that fits the crime that he committed that night."