Cops fired 10 bullets at an emotionally disturbed man because a confused officer screamed out he was being stabbed — when he’d accidentally been Tasered by a colleague, an explosive new lawsuit charges.

Police are claiming the officers who responded to Mohamed Bah’s Harlem apartment in 2012 opened fire — fatally hitting him with eight bullets — because he was lunging at them with a knife.

When they entered the dimly lit apartment, cops tried to subdue the African immigrant with Tasers and guns firing rubber pellets.

Officer Joseph McCormack fired his stun gun, striking Officer Edwin Mateo “from behind,’’ according to Bah family lawyer Randolph M. McLaughlin, of the law firm Newman Ferrara.

Mateo, who’d recently returned from a National Guard tour in Afghanistan, yelled, “He’s stabbing me. Shoot him,’’ according to the $70 million lawsuit, which is being filed Monday in Manhattan federal court.

The lawsuit also claims the 28-year-old Guinean was still alive, although barely, after being shot – but then was callously “dragged” by authorities through the building’s hallways, leaving a trial of “smeared” blood.

“First they shoot the man and treat him like a criminal – and then they drag him down the hallway like an animal,” said McLaughlin.

“Perhaps he’d still be alive if they just picked him up.

“This kind of behavior shocks the conscience and should not be tolerated on a civilized police force.’’

Two weeks ago, a grand jury empanelled by Manhattan DA Cyrus Vance found the cops — who had responded to a 911 call by Bah’s mother seeking medical help for her son — were justified in using deadly force and shouldn’t face criminal charges.

The Bah family’s lawsuit, which adds the new allegations to previously filed legal papers, relies on eyewitness accounts, police reports and other official documents, McLaughlin said.

It quotes Bah’s mother saying her son was still alive, if barely, when emergency responders tried reviving him outside the building.

He died soon afterward at a local hospital.

The lawsuit names as defendants the city, the NYPD, and the three cops who it’s believed fired the fatal shots: Mateo, Andrew Kress and Michael Green.

Bah’s mom says she called 911 not expecting armed cops brandishing tactical gear to show up.

She says she only wanted medics to treat her son, who suffered from depression.

McLaughlin said there’s another bizarre angle to the case.

The city probably won’t be able to introduce into evidence the knife cops claim his client was using to fight off the officers.

McLaughlin said he was told it mysteriously disappeared from a flooded police warehouse during Superstorm Sandy.

The NYPD — which is still conducting its own internal probe — referred questions to the city’s Law Department.

A Law Department spokesman said: “The case involves tragic circumstances,’’ and officials will “evaluate the matter thoroughly.’’