Manhattan Police are searching for 15-year-old Nadia Dunne , who disappeared from her Harlem apartment more than a week ago after a fight with her mom. She was last seen at her home on Adam Clayton Powell Boulevard near West 121st Street at 8 a.m. on Aug 13.

An East Village thief viciously beat a good Samaritan who intervened in a knifepoint mugging, authorities said yesterday.

The incident began at 5:20 p.m. Saturday, when Thomas Conni, 41, allegedly approached Sherman Sichler, 21, in a park at Avenue A and East Ninth Street.

Conni put a large knife to Sichler’s face and demanded money, cops said.

After Sichler handed over $70, John Pierson, 34, interceded and tried to retrieve Sichler’s cash from Conni.

Conni then allegedly took a long chain out of a backpack and repeatedly hit Pierson about the back and neck, inflicting cuts.

Police were called and arrested Conni, who was charged with assault and robbery, a spokeswoman for the Manhattan District Attorney’s Office said.

A Harlem man who was found shot last week died yesterday. Ervin Emanuel, 34, was discovered at the Harlem River Houses early last Thursday clinging to life and was rushed to Harlem Hospital.

Brooklyn A chair-wielding maniac was arrested for attacking a man at the victim’s Bensonhurst store, authorities said yesterday.

Ramel Gaynullin, 38, allegedly struck the 37-year-old man as he opened the door of his store on Stillwell Avenue near 86th Street at 10 p.m. on July 31.

After Gaynullin put the chair down, he grabbed a piece of metal and hit the victim with it, causing minor cuts, sources said.

Police grabbed Gaynullin on Monday after the victim spotted him in the neighborhood, cops said.

A man was busted in Williamsburg after stealing a car at knifepoint and ramming into a police cruiser, injuring a cop, authorities said yesterday.

The trouble began at 9:17 a.m. Monday, when Manuel Morales, 38, approached a 2000 Toyota at Wythe and Metropolitan avenues and threatened to kill the driver, sources said.

After the 51-year-old driver got out, Morales allegedly jumped behind the wheel and sped off.

As he traveled the wrong way down the street, he allegedly slammed into a police vehicle that had its lights and sirens on.

One officer was treated for neck and back injuries at Bellevue Hospital.

Staten Island A drunken man assaulted his girlfriend’s granddaughter after destroying some of the older woman’s property in their Tompkinsville apartment, authorities said yesterday.

Bernard Poirier, 61, returned intoxicated to the apartment on Victory Boulevard near Monroe Avenue at about 11:10 a.m. Monday.

He started arguing with his 67-year-old girlfriend and smashed her china closet, sources said.

Poirier then allegedly punched his girlfriend’s granddaughter when she tried to intervene.

Then he shoved the granddaughter and scratched her, causing minor injuries.

A drug-addled motorist was arrested after slamming his car into a dentist’s office in Graniteville, authorities said yesterday.

Anthony Delnegro, 37, was speeding down Richmond Avenue near Watchogue Road at 9:15 p.m. Monday when his 2006 Chrysler crashed into the brick wall of the office building, sources said.

When cops arrived, Delnegro admitted that he “took dust,” while possessing a bag of marijuana, cops said. He also allegedly reeked of booze.

Police nabbed a teen who robbed man after breaking into his Great Kills apartment, authorities said yesterday.

The incident began at about 9:30 p.m. Saturday, when a witness heard noises coming from an apartment on Cortelyou Avenue near East Figurea Avenue.

The witness called cops, who caught Nicholas Manzo, 18, with a stolen necklace in his pocket, authorities said.

A drunken motorist was arrested after cops spotted him driving the wrong way along an Oakdale street, authorities said yesterday.

Edward Moraski, 67, was swerving into oncoming traffic on Ridgecrest Avenue near Oakdale Street at around 10:45 a.m. Monday, when a police officer pulled over his 1995 Mercury Cougar, cops said.

When the cops ordered him out of the vehicle, Moraski allegedly opened the door and fell out, reeking of booze.

Police recovered a bottle of vodka and 10 Vicodin pills from the car.

Moraski, who failed a Breathalyzer test, was charged with DWI and drug possession, according to a spokesman for DA Daniel Donovan.