LONDON, England (CNN) -- A jury Tuesday acquitted three men of charges that they helped the bombers who carried out the July 7, 2005, attacks on the London transportation system.
Sadeer Saleem was accused of helping to plan the July 7, 2005 bombings in London
The four bombers died in the blasts, but Waheed Ali, Sadeer Saleem and Mohammed Shakil were accused of helping them by conducting reconnaissance and conspiring with them.
Two of the men -- Ali and Shakil -- were convicted of a second charge of conspiracy to attend a place used for terrorist training. They will be sentenced Wednesday, London's Metropolitan Police said.
Tuesday's verdicts came at the end of the men's retrial at Kingston Crown Court in southwest London. A separate jury failed to reach a verdict in their first trial, which ended in August after three months.
The bombings in 2005 killed 52 people in blasts on three subway trains and a bus. At least 900 people were wounded.
Police arrested the three in March 2007 after piecing together what they called a "complicated jigsaw with thousands of pieces." They were charged in April 2007.
Police said they analyzed more than 4,700 phone numbers and 90,000 calls. They discovered the three men had made a trip to London in December 2004 -- seven months before the fatal bombings -- which prosecutors claimed was a reconnaissance trip to scout potential targets.
Prosecutors said that on December 16, 2004, the men traveled from the northern English city of Leeds to London, along with Hasib Hussain, one of the July 7 bombers. When they got to the capital, they met with Lindsay.
Over the next two days, prosecutors claimed, the men visited tourist sites including the London Eye ferris wheel, the London Aquarium and the Natural History Museum, as well as underground train locations. Some of the spots, prosecutors said, were near where the July 7 bombs were eventually detonated.
Police called it "the first feasibility study" for the London bombings -- and whether they were looking at tourist or transportation sites, the men were seeking out potential bomb targets, police said.
The three men, who always denied the charges, acknowledged making the trip but said it was just an innocent outing to visit Ali's sister in London. Saleem told the court that he had had "no idea whatsoever" about the plot.
Traces of DNA linked all three alleged accomplices in some way to the bombers, police had claimed. Investigators found Ali's fingerprints on evidence found at the bomb-making sites.
Khan, Lindsay, Hussain and a fourth bomber, Shehzad Tanweer, set off a series of bombs the morning of July 7, 2005. They exploded on underground trains near Liverpool Street, Russell Square and Edgware Road and on a double-decker bus at Tavistock Square.
Police have previously said they believe others with knowledge of the attacks remain at large.
The jury found that in July 2001, Ali went with Khan to Pakistan. In July 2003, Shakil went with Khan to a camp in Pakistan, where the two undertook firearms training with machine guns, rocket-propelled grenade launchers, and AK-47 assault rifles, London police said.
The jury found Ali and Shakil guilty of conspiring to attend a place used for terrorist training, knowing or believing that instruction or training would be provided for purposes connected with the commission or preparation of acts of terrorism, London police said.
"Mohammed Siddique Khan and Mohammed Shakil told other attendees that their aim was to fight in Afghanistan," said John McDowall, head of the Metropolitan Police Counter Terrorism Command. "They were proficient in the use of and handling of terrorist weapons, and were certainly not enjoying a day out in a beautiful and mountainous area of Pakistan, as was suggested in court.
"Shakil himself accepted that the camp at Malakand was a serious business, whose purpose was to train willing volunteers to fight and kill in Afghanistan on behalf of the Taliban, a cause to which both he and Ali were, and remain, sympathetic," McDowall said.