A SECRET accomplice helped psycho “Batman” KILLER James Eagan Holmes carry out the horrific massacre at a Colorado movie theater, say crime experts who fear his co-conspirator is still at large!

Police claim Holmes acted alone during the July 20 bloodbath, but multiple eyewitnesses insist the self-styled redhaired “Joker” had help, and an expert tells The ENQUIRER that evidence points to a second person be­ing involved.

“It’s a perfect crime for an accomplice to avoid suspicion be­cause, with so much rage directed at Holmes, nobody has time to even consider the pos­sibility that he had help,” Wendy Murphy, a former prosecutor in Boston, Mass., told The ENQUIRER.

“It’s not easy to carry out such a prolific attack alone. It would make sense that he had a lookout, or someone who was helping him to carry all the weapons and ammuni­tion.”

And Murphy issued an ominous warning about Holmes’ accom­plice. “If that person is still out there, we could see another at­tack!” she said.

Holmes, 24, has been charged with 24 counts of murder and 116 counts of attempted murder in the epic act of violence that’s shocked America.

But a key witness insists that a second perpetrator opened an emergency exit to the Century 16 movie theater in Aurora, allowing a heavily armed Holmes to burst through it moments later.

Moviegoer Corbin Dates, 23, was sitting in the second row for the midnight premiere of “The Dark Knight Rises” as the horror unfold­ed.

“It seemed like there were two” people involved in the slaughter, said Dates, adding that the second man sported a goatee and seemed to be taking directions from someone else.

Witness Corbin Dates, who was sitting in the second row of the theater, says he saw a man sporting a goatee who, before the film started, answered a cell phone call, then got up and propped open an emergency exit door . The suspicious man “sat in the first right row and got a phone call,” continued Dates. “He took his phone and walked toward the emergency exit and was propping the door open with his foot. It seemed like he was making gestures trying to find somebody or trying to have somebody come to his loca­tion.”

Minutes later, Holmes burst through an emergency exit door and opened fire. Dates escaped the hail of bullets by diving to the floor and crawling to safety.

Yet another eyewitness claims Holmes “had someone with him.” Ac­cording to that person, two tear gas canisters were tossed from different areas in the theater by what appeared to be two different people.

In further evidence of a second per­petrator, audio recordings of cops at the scene reveal that other witnesses said there were at least two suspects.

“I’m getting multiple de­scriptions from the witnesses out here,” an officer told a dispatcher on one recording.

Holmes was dressed in black, but the cop told the opera­tor: “One of the shooters might be wearing a blue and white plaid shirt.”

Experts are also wondering how Holmes came up with the cash to buy his equipment and cache of ammo and guns.

On the night of the attack, Holmes was armed with an assault rifle, a shotgun and two Glock pistols, and he had stockpiled 6,000 rounds of ammunition. He also wore a ballistic helmet, gas mask, bulletproof vest, leg and groin protectors and tactical gloves as he blasted away.

Holmes bought the gear, guns and ammo, which cost an estimated $20,000, at gun stores and over the Internet. But he’d received only $26,000 in federal grant money for his neuroscience graduate program at the University of Colorado in Denver, and that grant money was released periodically.

The maniac had also rigged his third-floor apartment with more than 30 deadly explosive devices, includ­ing softball-size bombs crammed with gunpowder, glass containers of gasoline, tripwires and a control box in the kitchen.

Specialists spent two full days disarming the complicated web of explosives, and former prosecutor Murphy questions whether Holmes had the know-how to construct such an intricate trap, and how he financed his bloody assault.

“How does he suddenly have the thousands of dollars to buy military-grade weapons, much less know how to use them?” she said.

“He was never in the military and never visited a firing range that we know about.

“If there’s a witness saying Holmes may have had an accomplice, cops need to check that out.”