Similarly, the police said, there was no apartment for Mr. Klinger, though detectives found receipts in his pockets for two bank transfers: 50,000 euros sent on Jan. 8 and labeled “for property,” and a second, for 18,000 euros, from four days later that was marked “final payment,” according to an official who spoke on the condition of anonymity because the investigation was continuing.

Detectives believe that Mr. Bonich brought Mr. Klinger into Astoria Park on Jan. 31 just after noon on the pretense of showing him the surrounding area. Two passers-by found Mr. Klinger’s body there face down in the snow at 2:30 p.m. that day.

The police immediately homed in on Mr. Bonich, whose name Mr. Klinger had listed on his customs entry forms. Officers brought him in for questioning a day after Mr. Klinger’s body was found. The police said that around the same time they found video from outside Mr. Bonich’s apartment that showed him disposing of several garbage bags believed to contain Mr. Klinger’s belongings.

Image Alexander Bonich Credit... Ivor Hreljanovi

Over the course of 13 hours of questioning in a Queens police station, Mr. Bonich confessed to pulling the trigger twice, according to court papers filed by prosecutors.

He confessed again on Wednesday in an interview at a Brooklyn detention center, though the rest of his story diverged sharply from the account offered by the police and was at odds in its description of the very essence of Mr. Klinger’s personal life.

Dressed in gray prison garb, his gray hair standing up and the mustache he wore until recently shaved clean, Mr. Bonich denied taking any money from Mr. Klinger. Instead, he said that Mr. Klinger, in the throes of a midlife crisis, had come to the United States to meet a woman.