NAIROBI, Kenya -- All the terrorists died in a recent attack on a Kenyan mall, contrary to suggestions in a New York Police Department report that some of the attackers could have escaped, a Kenyan official said Thursday.

Somalia's al-Shabab militant group claimed responsibility for the Sept. 21 attack on Westgate Mall in Nairobi in which at least 67 people were killed.

Maj. Emmanuel Chirchir, a military spokesman, said that the bodies of the four attackers were discovered and dismissed suggestions, attributed to a New York Police Department report released this week, that some of the attackers could have escaped.

Chirchir dismissed the NYPD report, saying it used secondary information and that NYPD did not have representatives among the group of western investigators assisting Kenya with the probe.

At an NYPD briefing on Tuesday for corporate security officials, Lt. Kevin Yorke of the Intelligence Division presented an analysis of the Kenyan attack and the response by authorities there that he said was "based solely on open-source information we gathered and is unclassified."

Much of the presentation focused on closed-circuit footage of the four shooters during the first 12 hours of the siege. One segment showed the men hiding out in a storage area until one disabled a camera. Yorke said it was the last known images of the terrorists, and questioned why they weren't seen again even though other closed-circuit cameras around the mall were running for another 34 hours.

"That's the million-dollar question: Were the terrorists killed or did they escape? As cop, I'm very skeptical of any claims unless I see some proof," he said. "To put it politely, the Kenyan government has been vague and contradictory in their explanations. ... So while the Kenyan government says the terrorists are dead, killed in the rooftop collapse, there's a lot of doubt in my mind that it's true."

Western investigators, led by the FBI, have said it appears likely all four attackers died inside the mall. Kenyan investigators say they have identified three of the four attackers from pictures and DNA tests of the remains that were found. Three of the four attackers died of fire or smoke inhalation, said the Kenyan official who spoke on condition of anonymity because he is not authorized to share the information.

In court documents Kenya's Anti-terrorism Police Unit identifies two of the attackers as Hassan Abdi Dhuhulow, a 23-year-old Somalia native whose family moved to Norway in 1999, and Mohammed Abdinur Said, who a Kenyan official told the Associated Press was a refugee in Kakuma refugee camp in northwestern Kenya. Kenyan officials have not released the name of the third attacker that they say they have identified.

The four Westgate Mall attackers -- all ethnic Somalis -- crossed into Kenya in June and settled in Nairobi's ethnic Somali neighbourhood, where they worked out at the Andalus Gym, a Western official said last month.

None of the four had ever been to the U.S. or Britain, the official said.