By Chris Francescani and Curtis Skinner NEW YORK (Reuters) - New York police and retailers Macy's Inc and Barneys New York Inc traded blame on Tuesday over complaints by black customers who were stopped by police after making luxury purchases, in a case that has roiled civil rights leaders. The state's attorney general launched an investigation into security practices at the two department stores after four customers complained they were unfairly targeted in a series of cases the city's feisty tabloids have nicknamed "shop and frisk," a play on a controversial policing tactic. Barneys and Macy's officials said that police acted on their own, without input from store staff in choosing to stop shoppers who included a black actor with a role on a HBO series. Following a meeting in Harlem with New York civil rights leader Al Sharpton, Barneys Chief Executive Officer Mark Lee likewise said his employees had no part in two incidents at his stores. "We believe that no Barneys employees were involved in those incidents," Lee said. "No one from Barneys brought them to the attention of our internal security and no one from Barneys reached out to external authorities." Likewise, a Macy's spokeswoman denied that store staff had any role in two incidents at the company's Herald Square flagship. In one of those incidents, actor Rob Brown of HBO's "Treme" in June was paraded through the store in handcuffs after purchasing a $1,350 gold Movado watch for his mother, according to the Daily News. "This was an operation of the New York City Police Department," Macy's spokeswoman Elina Kazan said in a statement. NYPD chief spokesman John McCarthy countered those claims, saying that in both Barneys' incidents and the case involving Brown at Macy's, officers were acting on information provided by store security. "In both instances, the NYPD were conducting unrelated investigations" in the store, McCarthy said. Another Macy's incident, in which a 56-year-old exercise trainer named Art Palmer was surrounded by police after he used his credit card to buy $320 worth of shirts and ties, is still under investigation, McCarthy said. 'TROUBLING QUESTIONS' State Attorney General Eric Schneiderman gave the two department store chains until Friday to turn over information about their policies for detaining and questioning customers based on race. "The alleged repeated behavior of your employees raises troubling questions about your company's commitment to that ideal," Kristen Clarke, who heads the attorney general's civil rights bureau, wrote in letters to Barneys' Lee and Macy's Chief Stores Officer Peter Sachse released on Tuesday. After meeting with Lee on Tuesday, Sharpton and other leaders on Tuesday called for a summit with a "broad section" of city retail executives. "This must be done immediately," Sharpton said. "Not weeks - days, hours. There needs to be a meeting." Barneys and the New York City Police Department were named in a lawsuit filed by Trayon Christian of Queens last week. The lawsuit said police had detained him in April for two hours after he bought a $349 Ferragamo belt, and they then released him without charging him. Kayla Phillips, a 21-year-old nursing school student, said she was surrounded by four undercover police officers in February after leaving Barneys with a $2,500 Celine handbag she had purchased. New York's Civilian Complaint Review Board is investigating allegations of improper police stops of Palmer and Phillips, spokeswoman Linda Sachs said on Tuesday. Macy's has not yet responded to Palmer's allegation. In 2005, Macy's paid $600,000 to settle similar allegations that many of the chain's New York stores had targeted blacks and Latinos for particular scrutiny of theft, according to the New York Attorney General's office. Crime statistics from the New York Police Department show grand larceny has risen 31.6 percent over the past two years in the Midtown North precinct, which includes Macy's flagship store in Herald Square, and is up nearly 4 percent in the Upper East Side's 19th precinct, which includes Barneys New York. (Additional reporting by Barbara Goldberg; Editing by Scott Malone and Lisa Shumaker)