Kirsty MacColl’s stepmother says the person who killed her will never be caught.

Kirsty, who had hits like “Fairytale of New York” and “A New England,” died in 2000 when she was hit by a powerboat while diving off the coast of Mexico with her 13- and 15-year-old sons. She was 41 years old.

Guillermo Gonzalez Nova, the multimillionaire president of a Mexican supermarket chain, was in charge of the boat that was moving quickly and illegally in a designated diving area. But one of his employees took the blame and was fined $2,240 instead of going to jail for 34 months.

Jennifer Newlove, Kirsty’s mother, led the Justice For Kirsty campaign until she died in 2017.

Kirsty’s dad was the singer-songwriter and activist Ewan MacColl, and Peggy Seeger, 88, was married to him from 1977 until he died in 1989. She said, “Kirsty’s death was a complete and utter criminal tragedy.”

The man who killed her was not supposed to be there. He tried to get someone else to take the blame.

“It’s kind of like how our government works: they say one thing, then horrible things happen, and they continue with their plans.” I agree with what they said.

This is what power does. It has changed her sons’ lives forever.

Asked if Kirsty would ever get justice, Peggy said, “No.” Her mom was the only one who could have gone after them, and she did try.

“Being married to Ewan for a while made her politically aware of the fact that you can’t get to powerful people when they hide behind their power, especially in a foreign country.”

Peggy, an experienced singer and musician who will play at the Cambridge Folk Festival on July 28, says this about Kirsty: “Ahhhhhh.” She was my daughter by marriage. It’s too bad we didn’t work together. She was very clever. She could do a lot of things. She came up with great ideas.

“She probably would have flown.” She was scared to go on stage, though. For a while, she beat it.