(CNN) -- Four men behind what officials describe as the most serious Islamist terrorist plot ever hatched in Scandinavia were convicted of the plot Monday in a courthouse in Glostrup, just outside of Copenhagen, Denmark.
Three Swedish nationals and a Tunisian resident of Sweden were found guilty of targeting Jyllands Posten, the Copenhagen-based newspaper responsible for publishing controversial cartoons of the Prophet Mohammed.
The court ruled there was no doubt about their plan to attack and sentenced each of the men to 12 years in prison.
Counterterrorism officials in the United States and Scandinavia believe the plot was directed by al Qaeda operatives in Pakistan.
Authorities contend the four suspects planned a gun attack on the newspaper, to be followed by "the execution" of hostages.
It is possible a reception due to be attended by Denmark's crown prince in the same building as the newspaper was the intended target, a prosecutor said in court. The reception was to be held hours after the terrorist cell was arrested, but the prosecutor said there was no evidence the men were specifically targeting the crown prince.
The cell's plans were thwarted by a joint operation of Swedish and Danish security services, which tracked the suspects in December 2010 as they drove from Sweden to Denmark with a submachine gun, a silencer, and several dozen 9mm submachine gun cartridges, authorities say.
The four men convicted -- Mounir Dhahri, 46, a Tunisian citizen; Munir Awad, 31, of Lebanese descent; Sahbi Zalouti, 39, of Tunisian descent; and Omar Aboelazm, 32, of Egyptian descent -- are charged with plotting to kill a large number of people at the newspaper. They have denied the charges.
Western security services believe the plot was part of a broader al Qaeda conspiracy, authorized by Osama bin Laden, to strike Europe with operations mirroring the Mumbai, India, attack in November 2008, which killed nearly 200 people.
Dhahri, the suspected ringleader of the cell, Awad, and Zalouti had all traveled to Pakistan in early 2010. Awad and Zalouti, traveling separately, were arrested by Pakistani authorities in August 2010 before they could reach the North Waziristan region and were subsequently deported, according to a Swedish counterterrorism source.
During the trial, prosecutors pointed to a map showing Miramshah in North Waziristan and told the jury the plot had links to Pakistan, according to Elisabeth Haslund, a reporter for Berlingske newspaper, who attended the proceedings. But while the court ruled that Dhahri spent time in Waziristan, few details emerged in court on his movements there.
The court heard that Zalouti admitted to Swedish police he wired money from Sweden via Western Union to Dhahri in Bannu, a town bordering North Waziristan, according to Haslund.
Dhahri evaded capture in Pakistan, and he is believed to have received training there prior to returning to Europe shortly before the group began to plot their attack, according to the source.
At trial, it was revealed that Dhahri traveled back from Pakistan through Athens and Brussels, where Zalouti picked him up in a car. According to prosecutors, they then traveled to Copenhagen to case targets including the Jyllands Posten before traveling on to Stockholm.
Awad, the Lebanese-born suspect, had long been on the radar screen of Swedish counterterrorism services. He was suspected of having joined up with jihadist militants in Somalia in 2006 before fleeing the country when Ethiopian troops launched a military operation against Islamist militants there, according to a Danish security source.
By October 2010, Swedish security services had begun tracking the cell, placing listening devices in the men's apartments. A Swedish counterterrorism source told CNN the group did not settle on attacking the newspaper until shortly before the planned attack, and often squabbled.
Prosecutors stated that in the weeks before the plot was thwarted, there were 75 calls from a SIM card used by Dhahri to a number in Pakistan linked to "Masror," an individual suspected of involvement in terrorist activity. In court Monday, state prosecutor Gyrithe Ulrich argued the men deserved a significant prison sentence because they were "fulfilling a task ordered from Pakistan" and came close to carrying out their operation, according to Haslund.
On the evening of December 28, 2010, three of the cell members set off from Stockholm in a rental car with Dhahri at the wheel, authorities said. Security services continuously monitored their progress, including from the air. Zalouti bailed from the journey at the last minute, and was later arrested in Stockholm, according to court documents.
The court heard that after his arrest, he claimed to Swedish police he was aware that Dhahri -- his best friend -- and the others were planning an attack on the Jyllands Posten newspaper, but wanted out, according to Haslund.
Taking the stand in court, Zalouti said that at the time he only suspected a possible plot and had thought about calling police to alert them of his concerns after getting out of the car in Sweden, Haslund said.
It was just after 2 a.m. when the vehicle carrying the other cell members crossed the iconic Oresund Bridge connecting the two countries, authorities say. When they reached Copenhagen, they were initially unable to find the address where they planned to sleep. Just after 10 a.m. on December 29, Danish police, concerned the men might be about to try launch their operation, moved in to make the arrests.
Authorities say officials had already taken precautions. When they learned the group was planning to travel to Denmark, they secretly disabled their weapons, according to a Swedish counterterrorism source.
Plastic wrist strips were also found in their car, according to court documents, and security services said they believed the materials were going to be used to handcuff hostages. Security services believe the plan was to try to take up to 200 journalists hostage at the newspaper and execute many of them, a Swedish counterterrorism source told CNN.
The equivalent of $20,000 in cash was also recovered from the suspects, and a pistol and ammunition were found in one of their apartments, according to court documents.
A Swedish counterterrorism source has told CNN that investigations have revealed a complex set of connections between the plotters and a network linked to Ilyas Kashmiri, a senior Pakistani al Qaeda operative who Western intelligence believe orchestrated al Qaeda's plans to hit Europe with Mumbai-style attacks.
Dhahri and Awad had a connection to "Farid," a Stockholm-based militant of Moroccan descent who is suspected of acting as facilitator for Kashmiri's terrorist network, according to a Swedish counterterrorism source.
At trial, the prosecutor stated that in the days before the cell set off for Sweden, Dhahri was in touch by phone five times with Farid, using Zalouti's phone.
Also involved with Kashmiri's network was David Headley, an American of Pakistani descent who pleaded guilty two years ago to helping plot the Mumbai attacks.
According to an interview of Headley by India's National Investigation Agency that was obtained by CNN, Headley met with Farid in 2009 in relation to a plot Headley himself was planning against the Jyllands Posten newspaper.
The newspaper and its cartoonists have been targeted by several plots in recent years, including one by a Norwegian al Qaeda cell that was broken up in July 2010.
Kashmiri was reported killed in a drone strike in June 2011.
An attack strategy document seized on an alleged al Qaeda recruit in Berlin last spring indicates the terrorist group still hopes to launch a gun and hostage execution attack in Europe because of the publicity and fear such attacks would create.