Mark Oberholtzer isn't an Islamic fighter in Syria. He's never been to Syria. And the plumber from Texas City, Texas, says he certainly would never willingly aid fundamentalist rebels.

So it's hard for him to understand how his Ford F-250 pickup truck - including his logo for Mark-1 Plumbing and his phone number - wound up being in a photo posted on Twitter by the extremist Ansar al-Deen Front from the front lines of the war in Syria.

Mr Oberholtzer says he's been getting hundreds of phone calls and faxes since the Ansar al-Deen Front tweeted a picture of what appeared to be his old truck with an anti-aircraft gun in the back, according to the Galveston County Daily News.

However, it remains to be seen if the photo is entirely authentic, with a new video surfacing which suggests the photo could have been digitally altered.

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This truck, once owned by Mark-1 Plumbing in Texas City, Texas, is seen here in an Islamist propaganda photo. It's unclear if it has gone all the way to Syria or whether the photo has been digitally altered

This photo, taken from a propaganda video, shows a near identical scene featuring a different truck, raising questions as to the authenticity of the photo featuring Mr Oberholtzer's truck

The Islamist forces fighting across the region are known for their advanced and technical digital propaganda campaigns.

The video, featuring a different vehicle firing from exactly the same position, raises the possibility Mr Oberholtzer's vehicle may have been photoshopped into a video frame.

Superimposing a better vehicle and gun into a still frame from the original video would be significantly easier than trying to alter the video itself.

This could be why the video features an older model car and weapon, but the photo features Mr Oberholtzer's later-model Toyota.

Despite this, people have now been making hateful phone calls to Mr Oberholtzer's company in the mistaken belief he is supporting the fundamentalists.

'A few of the people are really ugly,' he told the newspaper.

Some threatened his life.

Mr Oberholtzer says he has hired a lawyer and wants to make Twitter remove the posting, CBS News reports.

He says he sold the truck to an AutoNation dealership three years ago.

In the past when he sold his work trucks, he always removed the logo first. The last time he got rid of a vehicle he didn't.

Mark Oberholtzer says he has no idea how Islamists in Syria could have got hold of his truck

Mr Oberholtzer, who has worked as a plumber for the past 32-years, assumed AutoNation would remove the decal before selling the truck.

Apparently it didn't.

It's still unknown how the truck could have made its way into the possession of Islamist fighters in Syria.

A spokesman for AutoNation told KHOU 11 News that the truck went to auction, and probably different owners over and over, before it may have ended up in the hands of Islamic terrorists.

Oberholtzer wants the death threats and the phone to stop ringing.

'We have a secretary here, she's scared to death. We all have families. We don't want no problems,' said Oberholtzer.

CBS News reports that the band of Ansar al-Deen seen in the photo mostly hail from Chechnya in Russia.

While most fighters are Islamic extremists, the group has not reportedly allied itself with ISIS in Syria.

ISIS: The terror group has expanded how and why it recruits new members and is specifically targeting sympathizers abroad

And while it is not known how fighters with ISIS could have come to own a Texan plumber's truck, the terror group is trying to expand how it recruits fighters to its ranks.

The extremist organization also has been targeting its sophisticated propaganda to entice potential wives and professionals such as doctors, accountants and engineers in its efforts to build a new society.

Among those it has lured were three teenage girls from Colorado, who set out for Syria this fall after swapping Twitter messages about marriage and religion with IS recruiters, and a young woman who sought to fight there - or failing that, to use her nursing skills. It's a diverse pool of recruits whose motives perplex Western governments seeking to combat the flow.

The group 'is issuing a bit of a siren song through social media, trying to attract people to their so-called caliphate,' FBI Director James Comey told reporters. 'And among the people they're trying to attract are young women to be brides for these jihadis.'

The group conscripts children for battle, recruits Westerners for acts of jihad and releases videotapes of beheadings. But it also uses propaganda with a humanitarian appeal, such as photos of bombed-out Syrian villages coupled with pleas for help. Video images of smiling children being given treats and enjoying stuffed animals paint a family-friendly portrait that suggests roles within the proto-state for wives and mothers.

Justice Department officials say people aiding the Islamic State understand what they're getting into and risk prosecution, whether or not they venture to Syria and even if they don't plan to take up arms themselves. Prosecutors have criminally charged more than 15 people in connection with supporting Islamic militant groups.

Advance: Militant Islamist fighters wave flags as they take part in a military parade along the streets of Syria's northern Raqqa province in June

A Rochester, New York, food store owner stands accused of trying to arrange for others to travel to Syria and of plotting to kill members of the U.S. military. An Illinois man, allegedly determined to join militants, left behind a letter saying he was disgusted by Western society. And prosecutors say a North Carolina man asked Allah online for martyrdom.

Most charges are brought under a statute that makes it illegal to provide 'material support' - including money, training or a false identity - to a designated terrorist group. Defense lawyers argued the law is overly broad and ensnares the misguided as often as it sweeps up the dangerous. Courts, however, have accepted an expansive interpretation of the law.

'We need to make clear that if you want to go over there and join a terrorist group, you're likely to end up instead in jail,' Carlin said.

Justice Department officials say they're also trying strategies other than prosecution, including trying to identify potential recruits before they go.

FBI agents in Colorado met repeatedly with Shannon Conley, a 19-year-old nurse's aide who had converted to Islam, hoping to dissuade her from traveling to Syria to marry a militant suitor she met online. Agents suggested she try humanitarian work instead of jihad, but she told them that if she couldn't fight, she would use her skills as a nurse's aide to help militant fighters, according to court documents.

Conley pleaded guilty in September and faces sentencing next month. Her lawyer, Robert Pepin, has said she was 'led terribly astray' while pursuing her religion and was 'saved' by her arrest.

Perhaps no case better shows the penetration of the recruitment campaign than that of the three Colorado girls, all from East African immigrant families, who were radicalized online and headed for Syria in October.

The self-styled 'caliphate' declared by the Islamic State group bridging Iraq and Syria is starting to show signs of strain

A review of the girls' social media use, which included thousands of Twitter messages and postings on other sites, by the SITE Intelligence Group shows they were in contact with online jihadists from around the world and were deeply interested in marriage and the role of women. As recruiters interacted with the girls, their typical teenage banter about friends and school became replaced with discussions of religion, paradise and death, the review showed.

Six months before they went overseas, one girl wrote that she wanted to get married as soon as possible and her friends wished her well, telling her they hoped she got an 'amazing husband because you do not deserve anything else!'

One female recruiter told prospects to expect to marry quickly and expect to live a domestic life, as it is 'completely impossible for women to participate in battle,' according to SITE. Women are expected to marry the fighters and bear their children, she explained. Another recruiter told a 16-year-old girl who inquired about joining that 'everyone is welcome,' according to the report.