LONDON — A judge on Thursday acquitted the only man charged with murder in Northern Ireland's deadliest terror attack, the 1998 car bombing that killed 29 people in the town of Omagh.

Judge Reginald Weir, who heard the case without a jury, said he was not convinced beyond a reasonable doubt that Sean Hoey was the bomb-maker behind the attack carried out by the dissident Irish Republican Army group, the Real IRA.

Hoey, 38, was acquitted of more than 50 charges, including murder, conspiracy to murder, causing an explosion and possession of explosive devices.

The Aug. 15, 1998, bomb killed mostly women and children, including an 18-month-old baby and a woman pregnant with twins.

The 500-pound bomb detonated inside a stolen car parked outside a clothes shop on Omagh's Market Street, less than 30 minutes after the first warning was sent to local media. Confusion created by the warnings led to police inadvertently shepherding victims toward the bomb site.

Prosecutors had tried to tie Hoey to the Omagh bombing and other explosions using DNA evidence. His lawyers claimed the evidence was unreliable.

After the verdict, the victims' families criticized police for their handling of the investigation.

"I'm very disappointed at the verdict, as are my family," said Victor Barker, whose 12-year-old son James was among the dead. Barker said the initial investigation was carried out with appalling inefficiency.

Before delivering his verdict, Weir sharply criticized the process of bagging, labeling and recording exhibits. He said police and some forensic experts had "slapdash approach" and "cavalier disregard" for the integrity of forensic items.

Weir said two police officers were dishonest in a deliberate attempt to bolster their statements and that it was impossible for him to accept their evidence.

He said he was not satisfied beyond reasonable doubt that the DNA evidence showed that all explosive devices were made by one person. Hoey faced charges related to 14 other explosions.

Detective Chief Superintendent Norman Baxter of the Police Service of Northern Ireland said his force would study the judge's verdict and see if there were any lessons to be learned. He said it was a very difficult day for his force, which is likely to come under heavy scrutiny over the ruling.

Hoey was arrested in 2005 following a review of forensic and scientific evidence.

Hoey's uncle, Colm Murphy, the only other man charged with involvement in the attacks, faces a retrial.

Murphy was convicted and sentenced to 14 years in prison based on telephone records allegedly showing he owned cell phones used by the bombers.

The conviction was overturned on appeal in 2005 when detectives who interrogated Murphy were found to have lied under oath about rewriting their notes of what he said while in custody.