The Big Apple convenience store on Western Avenue in South Portland was robbed shortly after midnight today – the second hold-up there since Sunday.

A man showed a knife and demanded money from the cash register and a safe, police said. The robber fled empty-handed after a brief struggle with a store clerk.

A short time later, police arrested Harold Adams, 44, of South Portland and charged him with both robberies.

Adams is being held in Cumberland County Jail on $100,000 cash bail. If convicted of robbery, a Class A offense, Adams faces up to 40 years in prison, police said.