NEW YORK — A 24-year-old nonprofit worker wept on the witness stand Tuesday as he described an unnerving episode of being handcuffed near his home while an officer took his keys and went inside his building.
Nicholas Pert, who is black, is one of about a dozen New Yorkers expected to tell their stories of being stopped, questioned, and frisked by police in a federal trial challenging how police use the tactic. About 5 million stops have been made during the past decade, mostly of black and Hispanic men.
The lawsuit challenges the constitutionality of some of the stops, with lawyers arguing the policy unfairly targets minorities.
City attorneys said officers operate within the law and do not target people solely because of their race. Police go where the crime is — and crime is overwhelmingly in minority neighborhoods, city lawyers said.
Pert’s mother died of cancer, and he is the guardian for his three siblings, two small boys and his disabled 20-year-old sister. The stocky community college graduate testified that he was stopped four times, starting on his 18th birthday.
But it was a stop in 2011 that reduced him to tears.
He testified that he was walking to the corner store about 11 p.m. to get milk when officers stopped him, handcuffed him, and put him in the back of a squad car. One officer took Peart’s keys, he said, and went into his building. Peart said he was concerned because he didn’t know how his siblings would react if the officer knocked on the door.
‘‘I was afraid he would go into my apartment, and I wasn’t there to take care of the situation,’’ he said.
Eventually the officer returned and he was freed.
Peart said, pausing to collect himself, that he felt criminalized by the episode.
‘‘To be treated like that, by someone who works for New York City, I felt degraded and helpless,’’ he said.
Lawyers for the Center for Constitutional Rights, which filed the class-action suit, are trying to show a pattern of racist and inappropriate behavior by the police.
Deon Dennis, another named plaintiff, testified that he was stopped outside his apartment in 2008 and officers accused him of drinking on the street, but he said he was not. Dennis, now 42, lives in Sumpter, S.C., and works in a chicken processing plant. He said he joined the suit for his children.
‘‘I don’t want them to grow up with what I had to for years,’’ he said.
City lawyers sought to discredit witnesses by suggesting their stories had evolved to become more dramatic, and their memories were faulty.
Peart testified that he filed one complaint against the police where he lied and said he had been physically injured.
He also said one of the stops happened in May 2011, instead of April 2011, had trouble recalling the race and descriptions of officers who stopped him, sometimes contradicting himself, and published angry Facebook posts insulting the Police Department.
Stop and frisk is legal, but the lawyers who sued say it must be reformed.
They are asking for a court-appointed monitor to oversee any changes ordered by the judge.
About half the people who are stopped are subject only to questioning. Others have their bag or backpack searched. And sometimes police conduct a full pat-down. Only about 10 percent of all stops result in arrest, and a weapon is recovered a small fraction of the time.
A police whistleblower, Adhyl Polanco, testified that his superiors only cared about arrests, summonses and stops. He said they told him he needed 20 summonses, five street stops and one arrest per month, or he'd face poor evaluations, shift changes and no overtime.
‘‘They can make your life very miserable,’’ he said.
Polanco was suspended with pay for years after internal affairs officers brought charges of filing false arrest paperwork; he says the charges came because he detailed a list of complaints to internal affairs.
The mayor and police commissioner say stop and frisk is a life-saving, crime-stopping tool that has helped drive crime down to record lows.