A bank robber running from police dropped a bag full of cash in the heart of Chinatown yesterday — but the money is still missing because an opportunist made off with the booty.

Police said the robber, who was not identified, walked into the TD Bank branch on Canal Street and Bowery at the foot of the Manhattan Bridge at about 1:30 p.m. He claimed to be armed and verbally demanded cash from a teller.

But just steps from the bank, a uniformed cop spotted the crook and chased him. As the robber ran, a dye packet inside the cash bag went off.

“I was right outside the bank. A man came running out,” said witness Bun Lam. “There was a cop two steps behind him . . . Right in front of a beauty-supply store, the ink exploded.”

The robber dropped the bag and continued to run, witnesses said, and another unidentified man picked up the red-stained cash and took off.

Cops caught up with the bank robber, but the booty-grabber was still in the wind.

Charges were pending.

jamie.schram@nypost.com