With the temperature expected to reach a record low on Monday, this year’s streak might have lasted well into the middle of the week, one police official said ruefully on Sunday, had it not been for Mr. Roman’s killing and another death in Queens on Saturday. In that case, which has yet to be ruled a homicide, a 56-year-old man was found dead in his basement with head trauma.

Detectives were questioning a man who had credit cards belonging to the victim, whose name had yet to be officially released. The police said the man, who has no listed address, admitted to knowing the victim from doing odd jobs around the victim’s home, just east of Flushing Meadows-Corona Park. He was taken into custody at a nearby gas station where he was offering to pump gas for drivers, to spare them the cold, in exchange for a few dollars.

The police were waiting on a ruling by the city medical examiner’s office on whether it was a homicide.

In the case of Mr. Roman, the confrontation that led to his death began just before noon on Friday. He and a friend were approached by two men on the sidewalk just outside Mr. Roman’s home on 89th Street in Woodhaven, according to the police.

One of the men pistol-whipped the friend, who then fled, the police said. The friend heard gunfire and returned to find Mr. Roman, 28, wounded on the steps of his home and the two men speeding off in a black Mercedes sedan, the police said.