Among other purchases, Beggs said Holmes bought two 6-ounce tear gas grenades over the Internet on May 10 and he went to a gun store on May 22 to buy one of his Glocks.

A little more than a month later, on July 1, a video camera captured Holmes as he bought a scope, a mount and some inert ammunition at a Colorado gun store, Beggs said.

In the video, Beggs said, Holmes' hair is dyed bright orange.

Four days later -- July 5 -- Holmes apparently visited the theater and used his iPhone to take pictures of interior doorways, Fyles testified

On July 7, Holmes used an online ticketing service to buy a ticket for the midnight showing of the movie, according to Detective Craig Appel, the lead investigator in the case.

He then returned to the theater two days later to take pictures of exterior doorways, Fyles testified.

The apartment

Witnesses detailed preparations that prosecutors believe Holmes made before setting out for the theater to turn his sparsely decorated Aurora apartment into a deathtrap.

At least some of the preparations were well under way by July 16, based on a photograph from Holmes' phone shown by prosecutors. In it, jars, wires, firework shells and other bomb-making materials are laid out in his kitchen.

By the time Holmes left, the carpet in his apartment had been soaked in oil and gas, FBI bomb technician Garrett Gumbinner testified. A container of glycerin hung above a frying pan with a potassium mixture, attached to a trip wire that would tip the glycerin into the pan, Gumbinner testified.

If triggered, Gumbinner said it would have set off an explosion and fire, igniting jars of homemade napalm spiked with bullets and thermite -- a metallic substance that burns so hot it is nearly impossible to extinguish.

In a diabolical twist that seems ripped from the pages of a comic book, witnesses said Holmes also rigged his computer and a boom box placed outside to begin playing loud music after he set out for the theater -- apparently in hopes that the noise would prompt someone to investigate and trigger the explosives.

Next to the boom box outside his apartment, Gumbinner testified, Holmes said he placed a toy car and a device that looked like it would control the car but would in fact set off the explosives.

Authorities recovered the boom box, bearing Holmes' fingerprints. The remote-control car device was never found, Appel testified.

A series of disturbing self-portraits displayed in court, apparently made sometime before Holmes allegedly left for the theater, according to data retrieved from his phone, show him in the eye-blackening contacts, his tongue stuck out in one, flashing a toothy grin and a handgun in another.

The shooting

Video from the theater shows a man they say is Holmes -- wearing dark pants, a light-colored shirt and a dark stocking cap covering his orange hair -- entering the multiplex before the movie begins.

The recordings show him going into Theater No. 9, a different theater from the one listed on his ticket.

While witnesses have not detailed in this week's preliminary hearing what investigators believe Holmes did once inside the theater, sources have said they believe he propped open the theater's back door and went to his car to put on body armor and arm himself. Authorities believe Holmes then re-entered the theater, tossing gas canisters before opening fire about 18 minutes into the movie, according to sources.

Witnesses who have spoken to CNN about the shooting have said the gunman roamed the theater, shooting people randomly as they tried to scramble away or cowered between seats.