The crime-fighting adventures of Lisbeth Salander and Mikael Blomkvist are not over: David Lagercrantz, the Swedish author who took on Stieg Larsson’s creations after his death, is to write two more novels in the Millennium series.

The novels are pencilled in for 2017 and, more tentatively, 2019, Swedish publisher Norstedts has announced. Lagercrantz, whose follow-up to Larsson’s bestselling trilogy was published in August, admitted that he couldn’t resist continuing the series.

“It has been so fantastically fun to write, and such a breathtaking adventure,” he said in a statement. “Also, I think I have a really good story.”

Larsson, a journalist, died in 2004 shortly after he delivered the manuscripts of the Millennium novels. He never saw his stories about punk hacker Salander and investigative journalist Blomkvist capture the imagination of the public, and go on to sell more than 80m copies around the world to date.

Lagercrantz, a respected journalist and author, was appointed by Larsson’s estate to continue the series in Det som inte dödar oss, published in English as The Girl in the Spider’s Web. The novel sees Salander hacking into the NSA and getting caught up in a murder. It has been heavily and publicly criticised by Larsson’s long-term partner Eva Gabrielsson; because she was not married to Larsson, his estate passed to his father and brother.

Gabrielsson has previously said that Larsson had begun a fourth Millennium novel – and, according to his British publisher Christopher MacLehose, Larsson “wrote down the shadowy outline of ten books” in the series before he died. But she does not support Lagercrantz’s continuation of the series. Earlier this year she told AFP she “wouldn’t have continued Stieg’s work. It was his language, his unique narrative … The worst thing is how saddened Stieg would have been. He never let anyone work on his literary texts. He would have been furious. Who knows, maybe he’ll send a lightning bolt at the book launch.”

According to its publishers, Lagercrantz’s The Girl in the Spider’s Web has sold 2.3m copies worldwide, topping charts in the US, UK, Germany, Italy and Spain.

“Reader reactions for Det som inte dödar oss have been so positive all around the world,” said Joakim Larsson from Larsson’s estate. “We are so happy and grateful for how David Lagercrantz has continued to write about the world and the characters that Stieg created. Now we are looking forward with excitement to how he will continue the story.”