A robber armed with a knife threatened a clerk at the Big Apple early Wednesday in Gorham, but fled the store with a Muscular Dystrophy donations canister after he couldn’t get money from a register.

A female clerk was alone on duty when the robber entered the store at 90 Main St., at 1 a.m.

Police are looking for a white male in his late teens or early 20s. The robber is described as 6 feet and weighing about 210 pounds. The police report said the clerk was threatened with a knife.

The clerk finished her shift at the store before leaving a few hours later.

“She didn’t get hurt, that’s the good side,” said store manager Jim Irish of Gorham.

Another store clerk later in the morning said the robber had demanded money from the cash register. The clerk on duty at that time apparently told the robber the register was computerized and wouldn’t open without a sale. The robber grabbed a toe warmer from a display near the register and tried to ring in it.

The robber banged on the computer, attempting to open the cash drawer. “He tried to open it and it wouldn’t open for him,” Irish said.

After several attempts, the robber left with the canister of donations.The amount of cash in the stolen canister is unknown. The store safe was locked. Gorham Detective Lawrence Maxfield-Fearon is investigating the robbery.

A robber armed with a knife stole, who couldn’t open a cash register, stole a donations canister from the counter of the Big Apple at 1 a.m. Wednesday.