A suspected double bomber on the FBI's most wanted list who vanished for 21 years is due in court this week to decide if he will be sent back to the United States to face trial.

The FBI believes Daniel Andreas San Diego has links to animal rights extremist groups and is their prime suspect for a series of bombings in the San Francisco Bay Area in 2003.

Former FBI agents have said there were missed opportunities to arrest the 47-year-old before he vanished, and claim they found a suspected bomb-making factory in his abandoned car after what detectives called a 65-mile (104km) rush-hour chase in California.

Mr. San Diego was found 5,000 miles (8,000km) away in a cottage in north Wales last year.

Mr. San Diego, who had a $250,000 (£199,000) bounty on his head, faces a five-day extradition hearing at Westminster Magistrates Court in London on Monday to find out if the UK will hand him over to the United States to answer a federal arrest warrant.

The former fugitive, the first born-and-raised American on the FBI's most wanted terrorist list, has been indicted by US prosecutors for maliciously damaging and destroying by means of an explosive after two separate attacks in 2003.

Animal rights extremist group Revolutionary Cells - Animal Liberation Brigade claimed responsibility for the attacks on firms they believed had links with organizations that tested products on animals.

Mr. Smith, a former FBI Special Agent, watched as the boot opened and admitted that it was everything you ever wanted. Had they known that, he stated, Mr. San Diego would have certainly been arrested days prior.

The FBI will not comment on the possible missed opportunities to arrest Mr. San Diego but assured that they will continue to seek accountability for his alleged crimes.

With his arrest now confirmed, former US agents are grappling with both frustration and relief that the man they spent years pursuing has finally been detained.