LONDON, England (CNN) -- Families of the victims of Northern Ireland's worst terror attack in 30 years of violence have criticized police over their handling of the case after a man accused of carrying out the atrocity was found not guilty on 29 counts of murder.
Sean Hoey was cleared Thursday on more than 50 charges relating to the 1998 bombing in the town of Omagh that killed 29 people and wounded more than 300 as well as other bombings and murders in Northern Ireland.
"It was an appalling catalogue of failure on behalf of the police," said Michael Gallagher whose son, Aidan, was killed in the bombing.
"A lot of people tonight have questions to answer," he added, saying that crime scene officers, forensic scientists and prosecution lawyers all shared responsibility for the courtroom failure.
Stanley McCombe, whose wife, Ann, 48, was another of the victims, said he was "flabbergasted and dumbfounded" by the verdict: "I do not know what to think. All the resources over the last nine-and-a-half years have not got us anywhere."
Senior police officers said they deeply regretted that victims and their families had not seen anyone brought to justice over the bombing.
"Our primary focus will continue to bring all those responsible for these crimes, most notably the Omagh bombing, before the courts," a police statement said. "Our investigations will continue and we would ask anyone with information about these crimes to come forward."
The Omagh bombing caused international outcry and gave fresh impetus to efforts to create a lasting peace between nationalist Catholics and pro-union Protestants in Northern Ireland.
Most of those killed and injured were shoppers enjoying a sunny Saturday afternoon when the 500-lb. car bomb of fertilizer and sugar exploded in the market area.
A telephoned bomb threat gave police the wrong location for the bomb, leading police to evacuate shoppers to the area where the car bomb was parked.
The Real IRA, which broke away from the mainstream Provisional IRA to protest the Northern Ireland peace process, ultimately claimed responsibility.
Hoey, an unemployed electrician, was charged in 2005 in what became Britain's biggest mass murder trial, but there were problems.
"There are instances where the evidence has been challenged and witnesses have been accused of being liars, police witnesses," said Alan Murray, a security journalist and author.
Hoey refused to testify. His lawyer criticized the prosecution during his summing up in the Belfast Crown Court.
"The crown's case had headed from low point to low point as witnesses lied and experts called to give testimony contradicted each other," lawyer Orlando Pownall said. "The prosecution's case could not survive."
Only one person has been convicted in connection to the bombing -- publican Colm Murphy a father of four, who was found guilty in 2002 of helping to plot the attack.
The leader of the banned Real IRA, Michael McKevitt, was convicted in 2004 and sentenced to 20 years in jail for directing terrorism, a law that was written after the Omagh bombing. E-mail to a friend