Despite claims by Canada and coalition forces of a near-perfect bombing record that has rarely harmed or killed civilians in Iraq and Syria, a fifth estate investigation has found nearly 50 credible allegations — involving as many as 600 possible deaths — that merit further review.

The fifth estate, The Hidden War: Map of Canadian airstrikes and reported civilian casualties from coalition bombing in Iraq and Syria.

The numbers are a sharp contrast to those provided by what's known as U.S. Central Command, which has publicly acknowledged only two civilian deaths and conducted only a handful of in-depth investigations.

"I don't expect (the coalition) to be happy about investigations, but recognize it's part and parcel of armed conflict," says Chris Jenks, a retired U.S. military judge advocate who investigated allegations of civilian casualties during the first Iraq war.

"When you are essentially blowing things up, when you are breaking things and wounding and killing people, investigations are gonna be part and parcel of that equation … [the coalition] should frankly want there to be investigations."

So far in the conflict in Iraq and Syria, Canada says it has conducted 181 airstrikes and dropped 469 bombs, but claims it has killed no civilians.

Human rights groups and independent observers, however, claim high estimates of civilian casualties.

Airwars, a London-based group of independent journalists documenting allegations of civilian casualties in this conflict, reviewed almost 250 allegations, determining more than 100 of them — involving as many as 1,000 possible deaths — to be credible.

A fifth estate investigation reviewed hundreds of allegations of civilian casualties stemming from coalition bombing raids in Iraq and Syria. (Canadian Forces Combat Camera) "[U.S. Central Command] reviews and investigates allegations of civilian casualties thoroughly and with great seriousness," Cmdr. Kyle Raines told the fifth estate in an email. "It's important to note that the current environment on the ground in Iraq and Syria makes investigating these allegations extremely challenging, and traditional investigation methods, such as interviewing witnesses and examining the site, are not typically available."

High number of 'credibility assessments'

While U.S. Central Command has conducted only a handful of in-depth investigations, it has conducted a higher number of what it calls "credibility assessments."

The U.S. military says it's aware of 100 allegations, and so far has determined 74 of them to be "not credible."

However, a fifth estate investigation that reviewed hundreds of allegations of civilian casualties stemming from coalition bombing raids in Iraq and Syria raises questions about the quality of the credibility assessments conducted by the U.S. and Canadian militaries.

It shows the assessments are at times conducted over a period of 24 or 48 hours and only involve reviewing photos and video from the air.

In one case, Canada was unaware its planes had been linked to an allegation of civilian casualties reviewed by the Pentagon.

Chris Jenks, a retired judge advocate general from the U.S. military, investigated civilian casualties in Iraq in during the first Iraq war. Investigations are essential, he says, at the very least to head off ISIS propaganda. (CBC) "This is completely unacceptable, in our view," says Chris Woods with Airwars. "And it undermines repeated coalition boasts that 'never in the history of warfare has an air campaign been this precise.'"

Child, woman allegedly killed in Syria

One of the allegations uncovered by the fifth estate investigation involves the alleged death of a child and a woman on July 30 in the Syrian town of Al Boukamal.

According to the Syrian Network for Human Rights, 17 others were also injured that day by coalition bombing.

Members of the jihadi militant group Islamic State posted photos of a child it claims died in the attack, using them as part of its anti-coalition propaganda. Despite being heavily critical of ISIS's conduct, the Syrian Network for Human Rights, whose work has been recognized by the United Nations, says it has verified the authenticity of the photos.

The coalition reported flying 17 bombing missions in that area on that day, including one Canadian mission.

This CF-18 fighter jet is part of the Canadian Armed Forces' contribution to coalition assistance to security forces in Iraq. (Combat Camera/DND) However, U.S. Central Command says it assessed the allegation as "not credible," while Canada says its planes are not responsible, because its bombing raid wasn't close enough to the location where the child died.

Both U.S. Central Command and the Canadian military declined to provide details of their reviews to the fifth estate — in Canada's case claiming "operational security."

The fifth estate investigation included meeting with a journalist working secretly behind Islamic State lines, in Mosul, to dig into allegations of civilian casualties.

The woman, identified only as "Laila" to protect her identity, claims she has seen the bodies of dozens of civilians killed in bombing raids, although the fifth estate couldn't independently verify her allegations.

It should be noted that the Iraqi air force also conducts bombing raids in the Mosul area.

Laila, however, says she trusts her sources.

A CF-18 Hornet engages in nighttime air-to-air refuelling during a coalition combat mission against ISIS. (Canadian Forces Combat Camera) "I don't deal with untrusted sources. They are the same sources I spoke to before ISIS [took over] and they are part of my people, so I have big trust in my sources. They are also working undercover like me. They come from various places, civilian, military and medical."

The end result, she says, is local people are starting to fear coalition planes.

"Unfortunately, the coalition airstrikes are hitting innocent civilians," she says. "Nowadays, the people of Mosul are afraid of both ISIS and the coalition."

For confidential tips on this story, please contact Timothy Sawa at timothy.sawa@cbc.ca or 647-382-7789.

Bob McKeown's full report on Canada's "Hidden War" airs Friday night on the season premiere of the fifth estate at 9 p.m. ET; 9:30 p.m. in Newfoundland and Labrador.