Twitter's hashtags offer a quick and easy way to find out what people are saying on a given topic. But for those who dislike what is being said there's also a quick and easy way to obstruct the discussion: they can summon an army of bots to flood the hashtag with irrelevant tweets.

This is a particularly common technique in the Middle East where political battles are now increasingly fought on the internet. The latest example concerns Jamal Khashoggi, the Saudi journalist who was lured to the kingdom's consulate in Turkey then killed and gruesomely dismembered – apparently at the behest of Crown Prince Mohammed bin Salman.

Scroll through the #JamalKhashoggi hashtag and you'll find multiple videos of an Australian land surveyor called Andy talking about how much he enjoys working for the Saudi oil firm, Aramco.

There are also videos of "Karl", "Dan", "Robert" and "Noel" – all similarly enamoured with life in Saudi Arabia. Other videos under the #JamalKhashoggi hashtag talk more generally about the kingdom's technological achievements and some Twitter accounts have been using the hashtag to promote the Crown Prince's views on Iran (examples here and here).

Most of the accounts tweeting with the #JamalKhashoggi hashtag and its Arabic equivalent ( خاشقجي# ) are probably bots, according to Marc Owen Jones who has been researching "inorganic" activity on the internet for several years.

Having identified 2,160 accounts using these hashtags he checked the dates when they were created and found some revealing anomalies. Almost half of them (933 acounts) had been created in March 2015 – indicating that they are likely to be bots.

Several smaller but significant blocks of accounts had been created at other times, most notably in July 2014 and September this year.

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In contrast to that, the number of accounts created at other times, presumably by genuine Twitter users, was tiny. For example, only 156 of them had been created between April 2008 and July 2013 – a period of more than five years.

The original source for videos and other content used in the bot-like tweets appears to be a satellite channel called Saudi 24 (@saudi24tv_news) which "has been behind hundreds of thousands of bots since 2012" according to Marc Owen Jones. He says an earlier Twitter account set up by the channel (Saudi_24) was suspended last year but reinstated after bots began campaigning on its behalf.

● More background: The Middle East's cyber wars