One of the five men arrested Wednesday was "so publicly exposed and known by the intelligence services that the plot against Jyllands-Posten was almost destined to fail," Magnus Ranstorp, a terrorism expert at the Swedish National Defence College, told the Politiken daily's online edition.
Munir Awad, a 29-year-old Swede born in Lebanon, was one of five men arrested Wednesday for hatching what Danish officials called a plan to "kill as many people as possible" in an assault on the Jyllands-Posten daily.
The paper published in September 2005 a dozen cartoons of the Muslim prophet that triggered violent and sometimes deadly protests around the world, as well as threats against the daily.
The four Swedish residents had all been under surveillance for months, Swedish intelligence service Säpo said this week.
Sweden's foreign ministry confirmed Friday that Awad had been arrested in Somalia in 2007 and in Pakistan in 2009 and that Swedish officials had intervened on his behalf.
Awad had publicly thanked Säpo for obtaining his release from Somalia when he was detained there three years ago with his then 17-year-old pregnant wife.
"We know Säpo brought us home and we are very grateful," he told a Swedish newspaper at the time.
In Pakistan Awad, his wife and their two-year-old son were arrested in the company of Mehdi Ghezali, a Swede who had spent two years in the US detention centre at Guantanamo Bay, ministry spokesman Anders Jörle told AFP.
Swedish news reports also said he had on and off had shared a Stockholm apartment with two members of the Islamist movement Al-Shabaab who were sentenced to prison by a Swedish court in December for "planning terrorist crimes" in Somalia.
"He is probably about the last man professional terrorists would send off on a mission to Denmark," Ranstorp said, adding he guessed the suspects in the foiled Danish plot were likely "semi-amateurs".
Petter Nessar of the Norwegian Defence Research Establishment said meanwhile that while Awad and his suspected accomplices may not have been ideal picks to carry out a professional attack, "terror cells need to use the resources they can get hold of."
"And even though the terrorists were not successful in carrying out the operation ... it has had a clear effect. People are frightened and that is the core essence of terror," he told Politiken.