'Father Courage' and his obsessive mission to track down son's killers

• Francisco Holgado tends the grave of his son Juan, who was murdered in a petrol station robbery 15 years ago. Picture: AP

Francisco Holgado, a quiet bank teller, plunged into the criminal underworld of Jerez de la Frontera, in southern Spain, after his son was stabbed up to 30 times during a petrol station robbery.

He infiltrated the gang suspected of his son's murder - four heroin addicts with a history of petty crime - and recorded their conversations with a hidden tape recorder.

"What is a father supposed to do?" he asked "A father whose son is murdered cannot just sit back at home. He has to give his life if necessary."

Mr Holgado, who has been dubbed Father Courage, has faced repeated obstacles on his obsessive mission. Last week, despite a judge's orders, police said there was no need to carry out new DNA tests on blood samples or fingerprints from the crime scene. Mr Holgado's lawyer will appeal, but says his hopes are slim.

In the early hours of 22 November, 1995, Juan Holgado, 26, was working at a petrol station ?when robbers burst in. During the robbery, Juan was repeatedly stabbed. He bled to death in a back office where he had tried to barricade himself. The attackers made off with a few hundred pounds in cash, cigarette cartons and some alcohol.

However, police mishandled the investigation. The first officers on the scene neglected to cordon off the area and reporters and photographers were allowed to walk around, contaminating the crime scene.

The company that owned the service station brought cleaners in the next day and reopened.

"It was like a bull in a china shop," then-Jerez police chief Jose Luis Fernandez Monterrubio later said of the investigation. "Evidence was destroyed."

Mr Holgado's double life began three years later. He called himself Pepe, donned a wig and tinted glasses and ventured into the drug-infested neighbourhood of La Asuncion.

He befriended the four gang members who often hung out in squats, where they smoked heroin and cocaine. Mr Holgado's main target was a young man named Pedro Asencio. He won his trust, he claims, by driving him around to buy drugs, or to a nearby town to see the young daughter who lived with his ex-wife.

As Mr Holgado played Pepe by night, he was still himself by day, waging a high-profile campaign to press authorities to solve his son's murder. Seven months after Pepe appeared in La Asuncion, he disappeared.

Mr Holgado's undercover life yielded more than a dozen 60-minute cassette tapes.But the most he got out of Asencio was an admission he had been with the other three suspects the night of the crime - and the young man vehemently denied taking part in the hold-up.

In the first trial in 1999, Mr Holgado's tapes were not admitted as evidence, on the grounds his lawyer unveiled their existence only after the proceedings got under way. The four were acquitted: none of the blood samples or fingerprints found at the crime scene could be traced to them.

In 2000, the Spanish Supreme Court ordered a retrial in which the tapes could be heard. In a retrial in 2003 the suspects were again acquitted - again because of lack of physical evidence.

Last August, a judge accepted a petition from Mr Holgado's lawyers for DNA samples and fingerprints to be re-examined by the National Police. But forensic experts said last week there was no need to redo the tests because they were done correctly the first time around.

Mr Holgado's quest has taken a high toll on his personal life. He took early retirement so he could focus on his mission. His three surviving children - two sons and a daughter - stopped speaking to him. "He's all about the publicity," said son Francisco, 37. Mr Holgado and his wife Antonia separated about eight years ago. Today, he still tours La Asuncion, combing the streets for a clue that might bring justice for his son.