Police vehicles drove through the Sweidi, Dhahar al-Budaih and Badr districts from Thursday night through Friday morning, but the authorities gave no indication they were any closer to finding Paul M. Johnson Jr., an employee of the U.S. defense corporation Lockheed Martin who was kidnapped last weekend.
Later Friday, security forces expanded their searches to other suburbs of Riyadh. Police stopped cars at checkpoints throughout the capital. FBI experts in hostage negotiation were standing by, reports CBS News Correspondent Steve Holt.
Former Deputy Minister of Interior Ibrahim Alebaji acknowledged the security forces' shortcoming on Saudi television on Friday. Speaking in a discussion program, Alebaji said: "Our security apparatus is not well trained in combating terrorism, but they are learning."
Meanwhile, Johnson's family was in seclusion. Police kept the media off the property outside the home of Donna Mayeux, Johnson's sister. An American flag and yellow ribbons were hung from the front porch, but there was no sign of activity inside.
Appearing on Saudi TV and struggling to hold back tears, Johnson's Thai wife pleaded for kidnappers to release her husband, saying "please bring him back to me."
"When I see his picture in TV, I fall down," Thanom Johnson said. "When I hear the name Paul Johnson, I cry a lot. He is my only family here."
Hundreds of supporters held candlelight vigils Thursday night in Johnson's New Jersey hometown and in Florida, where he lived before moving to the Middle East.
Johnson, 49, who has worked in Saudi Arabia for more than a decade, was kidnapped Saturday by a group calling itself al Qaeda in the Arabian Peninsula. At the time of his abduction, he was working on targeting and night vision systems for Apache helicopters.
In a statement posted Tuesday on the Internet, Johnson's captors threatened to kill him if al Qaeda prisoners in Saudi Arabia were not freed within 72 hours. The 72 hours ends sometime Friday. The kidnappers did not specify what time the countdown began or when it ends.
A senior Saudi official in the United States directly familiar with the investigation said Thursday night that U.S. and Saudi officials have had few promising leads.
The Saudi official, who spoke to The Associated Press on condition of anonymity because of the sensitive nature of the probe, said there had been no communications from the kidnappers except for the video and statement on the Web site.
More than 15,000 Saudi officers have been deployed in the search of Riyadh, going door-to-door in some neighborhoods. More than 1,200 Saudi homes had been searched as of Thursday night.
"We are even using the fire department, for instance, because they have knowledge of their neighborhoods, and districts," the official said.
People living in the districts where police have searched, which lie in western and southern Riyadh, suggested that the kidnappers enjoy popular support, partly because of U.S. policy in Iraq and its perceived backing for Israel.
"How can we inform on our brothers when we see all these pictures coming from Abu Ghraib and Rafah," Muklas Nawaf, a resident of Dhahar al-Budaih, said as he ate meat grilled on a spit at a restaurant called Jihad, Arabic for holy war. He was referring to the pictures of Iraqis abused by U.S. soldiers at the Abu Ghraib prison in Baghdad and Israeli military incursions and killings in the Gaza refugee camp of Rafah.
But the preacher of Riyadh's Imam Sultana Mosque implored the kidnappers to release Johnson in a column published in Al-Riyadh newspaper on Friday.
"O, youth of the nation who have trodden the wrong path, come back to the fold of the community of Islam. Avoid this sedition and be obedient to the ruler of the Muslims," Sheik Mohammed bin Saad al-Saeed wrote.
In a letter posted late Wednesday on Web sites where al Qaeda supporters and other militants leave messages, a man who identifies himself as Saad al-Mu'men — a pseudonym meaning "Saad The Believer," — urges militants to spare Johnson, saying killing him would violate Islamic law. "I will curse you in all my prayers" if he is harmed, it warned.
The writer also said Johnson had expressed opposition to U.S. foreign policy and an interest in converting to Islam.
On Thursday, Johnson's son, Paul Johnson III, pleaded for his release.
"I just want to ask the president of the United States and the Saudi officials to please make this happen," the son said in an interview on NBC. "Father's Day is right here. Bring my father home for Father's Day."
More than 200 people attended the Thursday night vigil in Port St. John, Fla., where Johnson's son still lives.
"We feel helpless here. I bet most people here have an awful feeling that this might be futile," said Father Tony Quinlivan of Blessed Sacrament in Cocoa, Fla. "But it's never futile when a community comes together."
"Your love, your prayers and your support are appreciated," said Johnson's niece, Angel Roork, at the gathering in Eagleswood Township, N.J., where about 100 people kept vigil.