Police tell lies in effort to cover up assault by one of their own.

NEW YORK - March 23, 2009 - A Brooklyn man ended up a paraplegic because a rookie cop "asserting his authority" made him tumble three storeys off a rooftop, the man's lawyer charged Monday.

Officer Jason Boreman may not have intended for Shawn Lewis to plummet to the ground when he shoved him on the rooftop, but it's his fault Lewis was crippled, said the lawyer.

"Absolutely no force was necessary at all," Lewis' attorney, Leslie Kelmachter, said in her opening statement to the jury in a civil suit seeking an unspecified amount of cash from the city.

Kelmachter accused Boreman of "asserting his authority" after catching the fleeing suspect after he harassed his ex-girlfriend in the building.

“Boreman said, ‘What are you doing running from the police?' and shoved him in the chest,” said Kelmachter.

Lewis toppled over a 2-foot-high parapet and fell to the ground, his lawyer contends. His spine was severed in the April 9, 2005, incident.

The suit accuses cops of concocting a coverup, claiming Lewis was hanging over the side of the building and lost his grip.

"No one pushed Mr. Lewis," said city attorney Susan Scharfstein, adding that there are differing accounts of what happened.

At one point, Lewis admitted to NYPD Internal Affairs investigators that he fell accidentally, said Scharfstein.

Sgt. John Marchello testified that he was on the roof and although he did not see what happened, he told his superiors that Lewis fell from the side of the building because that was his "logical assumption."

Marchello confronted the seriously injured man on the ground in an alley below and pointed his gun at him. "I said, 'Police, don't move!' and he said, 'I can't move,'" Marchello said.