A thief assaulted a woman in her Upper East Side apartment building and ran off with her Louis Vuitton purse, police sources said Saturday. The 33-year-old woman was on her way home from work when a man followed her into the building at West 101st Street and West End Avenue at 5:15 a.m. Friday, cops said. He punched her in the face and fled with her purse worth $800. He punched her so hard that she suffered hearing loss in the left ear, sources said the victim claims. The woman was rushed to Bellevue Hospital for severe facial pain and swelling, cops said.

A thug swiped an elderly woman’s purse at a Midtown supermarket and then went shopping for electronics, cops said Saturday. The thief grabbed the 76-year-old’s bag from a shopping cart in the Whole Foods on East 57th Street on April 4. He then spent $1,300 on the woman’s credit card to buy an iPad and a Samsung Galaxy Note from a Radio Shack on Third Avenue, police said.

A gunman robbed an Upper East Side doughnut shop of $250, cops said Saturday. The thief, who was wearing a gray, hooded sweatshirt with a large American flag on the front, entered Dunkin Donuts on East 70th Street at 9:45 p.m. Friday and pointed his weapon at a clerk before fleeing with the cash, police said. The same man is believed to have tried to hold up a candy store on Amsterdam Avenue the day before. In that incident, he pointed two guns at a 57-year-old worker before fleeing empty-handed.

The January death of a woman on the Upper East Side has now been classified as a homicide, said police Saturday. The victim, Reisa Paez, 43, was discovered in her fifth-floor apartment at the Isaac Holmes Houses at First Avenue and East 92nd Street at 5 p.m. Jan. 17, cops said. The victim’s cousin, Kevin Baez, 30, a lead suspect, was found dead later that day in his hometown of Framingham, Mass., in an apparent suicide, sources said. The medical examiner said Paez died from a blow to the head.

A brave 24-year-old was able to free herself from the grips of a persistent armed robber in Greenwich Village, cops said Saturday. The victim was inside a residence at 78 Fifth Ave. at 8:45 p.m. Tuesday, when she was first met by the gun-wielding creep, police said. The thug demanded that she let him in. After the victim said she didn’t live in the building, the crook led her outside by the hand, in the hopes of fetching a taxi so she could withdraw loot from an ATM. But as the cab was approaching, the daring victim was able to break free, sources said.

A secretary for L’Oreal Paris on Fifth Avenue has been charged with making $130,000 in illegal charges on a company credit card, authorities said. Jenny Keo, 28, used a MasterCard to charge travel, food and limousine services while she worked for the cosmetics company in its tony Midtown offices from 2011 to 2015, court papers state. A L’Oreal security officer finally noticed the unauthorized charges and informed police. Her attorney, Bruce Yermen, told The Post, “Jenny is innocent of the charge.”