Police say they’ve captured a conniving 14-year-old who allegedly made off with a sight-impaired gentleman’s wallet — by claiming he was a cop who could help guide him into the subway near Penn Station.The authorities had been searching for the nervy tyke since Monday, when he approached the 64-year-old victim at 34th Street and Eighth Avenue.The kid only came up to the victim’s shoulders — but nevertheless “identified himself as a police officer and offered him assistance,” in getting into the subway, police said.Subway surveillance shows the sight-impaired man waiting calmly as the kid brazenly unzips the man’s back pack and removes his wallet.The practically Kindergarten cop then bolted, police said — quickly using his victim’s credit card to ring up $500 in merchandise at a nearby retail store.The boy, whose name was not revealed due to his age, has been arrested and charged with grand larceny and criminal impersonation of a police officer.