After the dramatic release of six men falsely imprisoned for a guerrilla bombing 17 years ago, British police began investigating their own ranks Friday and resumed the search for the real culprits.

Home Secretary Kenneth Baker said police had set up a team to find the attackers, adding that another team was investigating police officers accused of lying in the case.The Irish Republican Army (IRA) claimed responsibility for the 1974 bombings at two pubs in Birmingham, in central England, in which 21 people were killed.

It was the most deadly attack in mainland Britain by the IRA, fighting to end British rule in Northern Ireland. It stirred national outrage and pressure for police action.

The "Birmingham Six" were arrested a year later, but quickly alleged their confessions had been forced.

The six were freed by three appeal court judges Thursday, their emotional reunion with families and friends outside London's Old Bailey courthouse shown in television news bulletins across the country.

The appeals court that cleared the men found their statements had been falsified and also threw out forensic and scientific evidence used to convict them.

Law reformers called their imprisonment one of the gravest miscarriages of justice in British history.

Opposition Labor Party member of parliament Chris Mullin, who campaigned for the release of the six men, has claimed he tracked down the real bombers.