Saudi Arabian security forces reported Wednesday that they had found the severed head of a slain American hostage in a suspected hideout for Islamic radicals in Riyadh, the capital.

The head of Paul M. Johnson Jr., an employee of Bethesda-based Lockheed Martin Corp. who was killed a month ago, was discovered late Tuesday in a freezer during a search of a building that Saudi officials described as a safe house for an extremist group calling itself al Qaeda in the Arabian Peninsula. The rest of the body was not found.

Saudi security forces killed two suspected members of the group and wounded three others in a gun battle in the King Fahd district of Riyadh, government officials said. Among those killed was Issa Saad Oushan, who was on a list of the 26 most-wanted terrorism suspects in the kingdom, according to a statement released by the Saudi Interior Ministry.

Security forces also captured the wife and three children of Saleh Awfi, the self-proclaimed leader of the group, which is affiliated with Osama bin Laden's al Qaeda network, Saudi officials said.

Johnson was kidnapped June 12 after he left work near King Khalid International Airport outside Riyadh. On the same day, an American co-worker was slain by gunmen in his garage, also after leaving work. A week later, al Qaeda in the Arabian Peninsula posted a videotape on the Internet showing Johnson's decapitated body.

Within hours of the posting, Saudi security forces tracked down Abdulaziz Muqrin, then the leader of al Qaeda in the Arabian Peninsula and the man who asserted responsibility for Johnson's killing. Muqrin and three others died in a shootout at a Riyadh gas station, but a dragnet by thousands of Saudi police officers and other security agents was unable to find Johnson's remains.

Last week, the U.S. Embassy in Riyadh announced that the search for the remains had been called off after more than a month of fruitless effort. Saudi officials said their investigation would continue.

On Wednesday, the Saudi ambassador to the United States said that authorities would continue to search for the rest of Johnson's body. "We have been committed to doing everything we can to find the remains so that he can have a proper burial and the family can bring closure to this tragic situation," Prince Bandar bin Sultan said in a statement.

More than 85 people have died since al Qaeda-linked groups began a series of suicide bombings, kidnappings and other attacks in Saudi Arabia in May 2003.

No attacks have occurred since Johnson's death, although Saudi security forces have skirmished with suspected radicals on several occasions. According to government reports, security forces have captured or killed at least 15 of the 26 suspected terrorists on the kingdom's most-wanted list.