LONDON — A 52-year-old con man with 28 convictions pleaded guilty to fraud on Thursday for having tried to collect 12,500 pounds, or about $16,000, in financial assistance by falsely claiming that his family had died in the Grenfell Tower fire in London.

Anh Nhu Nguyen, a Vietnamese man who lives in southeastern London, posed as a survivor for at least two weeks after the fire on June 14 that killed at least 80 people. He said that his wife and son had perished in the blaze and that he had lost all of his “worldly possessions.”

After registering at a relief center for disaster victims in June, Mr. Nguyen was given free accommodation worth more than $3,000 at a nearby Holiday Inn as well as food, electrical goods and money from various charity funds.

After the fire, he gave extensive interviews to several news organizations claiming that he had become separated from his wife and 12-year-old son as they tried to escape from the tower’s 15th floor through a smoke-filled stairwell. He said that when he tried to go back and find them, he had been stopped by firefighters.