An unwelcome guest spent the weekend stealing cellphones, laptops, cameras, credit cards, and cash from rooms at the Boston Park Plaza hotel, police said Sunday night. Paul Palrao was arrested Saturday morning for allegedly trespassing at the Hyatt Regency Boston. After Palrao’s arrest, detectives found that he matched the description of a suspect who had burglarized the Back Bay hotel, said David Estrada, a Boston Police spokesman. Guests in at least five rooms at the Park Plaza reported Saturday morning that items had been stolen from them overnight, Estrada said. Many of the stolen goods were later recovered, Estrada said. Investigators were trying to determine Sunday night how the burglar accessed the guests’ rooms, Estrada said. Police are also investigating if the burglar had help and if similar incidents have been reported at other hotels, he said. Palrao, 35, of Boston, is scheduled to be arraigned Monday in Boston Municipal Court.