The video footage published on an Islamist website of American Paul Johnson and the subsequent image of his severed head and body represents another step in the evolution of Islamic extremist tactics in Saudi Arabia.
By Gordon Corera
BBC security correspondent
It also serves to emphasise once again the degree to which the militants have a sophisticated understanding of how violence, the media and public opinion can interact.
The aim of showing video footage of hostages is to spread fear
In Saudi Arabia, the first major attack in recent years by al-Qaeda supporters came in May 2003 when a housing compound was bombed.
But this was widely seen as having been a setback for the radicals because so many Muslims were killed, alienating many people within the kingdom.
By the time of the Khobar attack on 29 May of this year, militants showed they had learned that lesson.
After they stormed a compound they were careful to separate out Muslims from non-Muslims and only kill Westerners.
In the last few weeks, we have also seen the arrival of more targeted attacks - specific individuals singled out for either assassination, as happened with two Americans in the last 10 days or, as in the case of Paul Johnson, for kidnapping.
Militants appear to be constantly shifting tactics to find the best means of achieving their aims, often watching what has been effective in other countries - particularly Iraq where hostage-taking has risen sharply in the last few months - and then translating those methods to the local context.
Impact on opinion
They are also acutely conscious of the impact their actions can have on opinion and especially within the key battleground of broader Islamic opinion, where some have reacted strongly against the killing of other Muslims, although many others have also rejected the killing of Westerners.
Hostage-takers have also tried to win over that broader block of opinion by claiming that American actions at the Guantanamo Bay naval base on Cuba and Baghdad's Abu Ghraib prison - which have caused widespread outrage - justify their actions.
A similar evolution of tactics may also have occurred with other radical jihadist groups.
In Indonesia for instance, there have been reports that Jemaah Islamiah may have turned away from large scale bombings and towards assassinations of key figures again because of the negative publicity surrounding Muslim casualties in previous attacks such as that against Marriott Hotel in Jakarta last August when 11 Indonesians and only one foreigner was killed.
The evolution of tactics relates to the broader battle for public opinion, both within countries like Saudi Arabia as well as in the Western world.
In the case of Mr Johnson, the militants almost certainly know that the demands they have made - for all of their fighters to be released from Saudi prison - cannot possibly be met.
Instead, the aim of the hostage-taking and the video is to spread fear.
One part of their plan is to spread fear amongst the six to eight million foreign workers who are a vital part of the Saudi economy.
American and British citizens are especially important in the oil industry and the hope is that by making these people flee the country, they can destabilise the economy and ultimately undermine the royal family.
As well as among expats, the militants are also seeking to influence opinion back in the US and in other Western countries.
Reaction to attacks like this may have an impact on groups' tactics
The battle between the al-Qaeda network and the West is as much a psychological war as one fought with traditional weapons.
The aim of the psychological war is to break your opponent's will and militants have learned that hostage-taking can be a powerful tool in their arsenal.
Video footage of previous hostages has had a profound impact on public opinion - most recently in the case of US journalist Daniel Pearl, who was killed in Pakistan, and also Nick Berg, killed in Iraq.
If you go back even further, the taking of hostages in the American Embassy in Tehran after the Iranian revolution in 1979 is considered to have had a major impact on the 1980 presidential election, when President Jimmy Carter was ejected from office after attempts to secure their release failed.
By using the full array of modern media like video production and websites, the militants are showing their awareness of just how much impact they can have through the taking of an individual hostage.
The fear for those living in Saudi Arabia may be that this is only the beginning of a new phase in a growing threat that appears to have no end in sight.