Police are trying to unravel the mystery of a wounded man found tied up in the trunk of a BMW in upper Manhattan this morning.

Around 9:40 a.m., the BMW, sliding on the icy roadway, rear-ended a livery cab at the intersection of 10th Avenue, Dyckman Street and Harlem River Drive in Inwood, said cops.

The BMW’s driver tried to back his car away from the crash.

But unable to get any traction in the snow, he jumped out of the car and fled on foot.

It was unclear if the BMW’s driver was armed.

When cops arrived, they noticed the BMW’s rear seat had been pulled up. So they pulled the seat all the way out, and saw a man tied up in the trunk.

The man, who was unconscious, had head trauma, said police sources. It was unclear whether his injury was caused by a blade or a gunshot.

"He looked unconscious. He was lying there and he looked half dead .¤.¤. He wasn’t wearing shoes or socks," said witness Vera Marino, 45, who was shoveling snow at a nearby school when cops arrived.

The unidentified man was taken to Harlem Hospital, where he was listed in stable condition this afternoon.

Because the man hasn’t spoken to police, officers will have to fingerprint him to learn his identity.

A New Jersey man who was severely beaten - and part of whose ear was hacked off - was found tied up inside the trunk of a BMW that crashed in upper Manhattan early Wednesday, police said.

The victim survived the harrowing ordeal despite spending a frigid night trapped inside the trunk, police sources said.

Detectives believe they have identified the mysterious driver, who ran away from the wrecked sports car - and its incriminating cargo - in Inwood shortly after 9 a.m.

The driver, who goes by the name of Blake, slammed the luxury sedan into a livery cab after running a red light on snow-covered Dyckman St., near an exit for the Harlem River Drive, the sources said.

The cabbie, Muntaru Iddrisu, 47, said the suspect tried to flee the crash by making a U-turn, but got stuck in the snow. Iddrisu said the suspect, whom he described as black and wearing black jeans and a black jacket, got out of the car and asked if he was okay.

"It was just a flash - and then he walked away," Iddrisu said.

When police arrived, they spotted what looked like a bullet hole in the blue BMW's trunk, which also had blood spots on it, the sources said.

They popped the trunk open and found the victim, bound and barefoot, with the bloody remains of one of his ears dangling from his head, the sources said.

He was unconscious. His head had been sliced with a knife and beaten so hard that his neck was broken, the sources said. Paramedics rushed him to Harlem Hospital. He was in critical condition Wednesday night, breathing through a respirator. Police officials refused to release his name.

Investigators think the victim may have been selling the 2008 luxury coupe to the suspect, whose name was on a bill of sale found inside the car, the sources said.

But one of the sources said investigators at one point thought the victim had been abducted and brutalized as retaliation over a simmering, drug-related feud.

The suspect, who was still at large Wednesday night, has been arrested multiple times in the past, including one collar for participating in a cockfight, the sources said.

He lives in the Dyckman Houses, near the site of the crash, the sources said.

Investigators believe he may have driven the BMW to his home about 4 a.m. Wednesday - with the victim inside the trunk, the sources said.

Iddrisu said he hopes police catch him so he doesn't have to live in fear.

"This is New York, anything can happen," he said, acknowledging his dread.