Simple reasoning question

On a winter evening, the Maori detective, who was on vacation, strolled out of the hotel, intending to admire the winter scenery by the nearby lakeside. It was very cold outside, with the temperature at minus 5 degrees Celsius, and Maori instinctively raised the collar of his leather coat. Suddenly, a man, soaked from head to toe, ran towards him gasping for breath, not bothering to take off his clothes to wring them out, and shouted to Maori: "Sir! Please save my friend. We were ice skating on the lake just now, and the ice cracked. He accidentally fell in. I jumped in to try to rescue him for a long time but couldn't get anything." Maori hurried back to the hotel to get help. The distance from the hotel to the accident site was 1,500 meters. When they arrived, all they found were a pair of ice skates next to the crack. The man explained: "I had just taken off my skates at the time, but he insisted on playing for a while longer." Maori stared at him: "Stop hiding the truth. Let's talk about how you actually caused your friend's death!"

How did Maori uncover the deception???

It's actually very simple.
By the way, a note to the mystery puzzle team members: since I start my formal job tomorrow, I might not be able to post puzzles regularly in the future! Sorry!