|From right, Omar Said Omar, and Mohammed Nablan, in civilian clothes, with prisons security guards after they were released, together with Mohamed Kubwa, second from left, top, and Aboud Rogo Mohammed, fourth from left, top|
Each of the four suspects faced 15 counts of murder in connection with the blast.
High Court Justice John Osiemo told the court, prosecutors had failed to prove that the suspects were at the scene of the bombing, had met with the men who carried out the attack, or were otherwise involved.
Defense lawyer Maobe Mao says much of the prosecution's case rested on a tenuous link between the suspects and alleged al-Qaida operative Abdi Karim.
"Throughout the trial, you were taken through what I would call a sideshow," he said. "There was no attempt whatsoever to say, accused number this has done this, and it has led to the killing. What they were merely trying to say or do in this case was to say so-and-so, you received a call or made a call to a number that belongs to Abdi Karim, and you, therefore, are responsible for these murders."
The al-Qaida network had claimed responsibility for the November 2002 attack on Paradise Hotel near the port city of Mombasa.
Throughout the trial, prosecutors had maintained that there was sufficient evidence to convict the suspects.
There are three suspects still facing charges of conspiracy to commit murder in connection with the bombing and other charges related to an attempt to shoot down an Israeli aircraft in the area.
Judgment on their case will be delivered later this month.
Human rights groups had blasted the government for the lengthy trial and detaining the suspects for more than two years.
Mr. Mao says his clients plan to take legal action against the government for their long detention.