London, UK (BBN)-A growing number of defectors from the so-called Islamic State are speaking publicly about their decision to leave, according to a new report.
The defectors risk reprisals by members of the militant group and imprisonment by their home nations, the report says, leading most to go into hiding, reports BBC.
But researchers at King's College London found 58 defectors had spoken out, two-thirds of them this year.
The report suggests their testimonies could help to discourage new members.
The International Centre for the Study for Radicalisation (ICSR) at King's College, which published the report, estimates that hundreds of former militants have now defected or attempted to defect.
Dozens are thought to have made it out via Turkey while others have reportedly been caught and executed. The ICSR claims that the 58 cases in their study are "likely only a fraction of those disillusioned, ready to defect and/or willing to go public".
'UN-ISLAMIC BEHAVIOUR'
The researchers identify several key narratives among the reasons for leaving IS. Most defectors said they were concerned with brutality against fellow Muslims and perceived "un-Islamic" behaviour among members, including corruption.
Some admitted they were disappointed with the quality of life under IS.
"They were typically among the ones who had joined the group for material and 'selfish' reasons, and quickly realised that none of the luxury goods and cars that they had been promised would materialise," the report says.
Two fighters said they defected after learning they were to be suicide bombers. Speaking to the BBC last year, one defector, who asked not to be named, said the "brutality of IS terrifies everyone".
"Anything that contradicts their beliefs is forbidden. Anyone who follows what they reject is an apostate and must be killed," he said.
Another Western recruit, Ibrahim, told CBS: "A lot of people when they come, they have a lot of enthusiasm about what they've seen online ... It's not all military parades or it's not all victories."
The report suggests that stories of disillusionment could help to discourage new recruits.
"The defectors provide unique insight into life in the Islamic State," it says.
"But their stories can also be used as a potentially powerful tool in the fight against it. The defectors' very existence shatters the image of unity and determination that IS seeks to convey."
The US is already fighting a propaganda war against the group. Among its tools are a State Department-run Twitter account named "Think Again Turn Away" devoted to pushing out anti-IS messages.
But the ICSR urges governments to do more to encourage former IS militants to speak out, including removing legal obstacles such as prosecution on terror charges.
The report acknowledges that many of the defectors may have committed crimes and have an incentive to "say whatever they think will save them from prosecution or worse".
But it said the narratives compiled by the ICSR were "so strong and consistent" with other accounts that they could be regarded as valid.
The earliest cases compiled in the report date from January 2014 and the most recent from August this year.
Overall, two thirds of cases occurred during the first eight months of 2015 and one third in the summer months alone.
BBN/SK/AD