SAN BERNARDINO (CBSLA.com) — San Bernardino authorities Wednesday acknowledged they set off fire-causing pyrotechnic tear gas in a battle with murder suspect Christopher Dorner — but insisted they didn’t burn down the cabin where they believed he was holed up on purpose.

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“We did not intentionally burn down that cabin to get Mr. Dorner out,” said San Bernardino County Sheriff John McMahon.

He said sheriff’s first used conventional tear gas but it didn’t have the desired effect.

The pyrotechnic tear gas (also called incendiary gas) is known to start fires.

Dave Bryan, CBS2 and KCAL9 political reporter, says the pyrotechnic tear gas is not used at demonstrations or to disperse crowds for that reason.

The fire effectively ended the blazing gun battle and violent standoff between sheriffs and Dorner.

Bryan spoke to retired FBI agent Steve Moore who said the fire-causing nature of pyrotechnic tear gas is why it is often not used.

He says it causes fires “routinely.” And he added, “I have never been on an operation where it was deployed. And I worked [alongside] SWAT full-time for five years.”

Moore believes it would have been “suicidal” to send a strike team into the cabin to try to get Dorner out. “Sending an assault team into that house would have been horrendously dangerous. From my understanding, he may have had an AR-15 an M4. You can engage people very effectively to 400 yards with that. And it is withering [gun]fire.”

In the end, Moore believes San Bernardino sheriffs didn’t have much choice but to use the less conventional tear gas. “They were in a life and death struggle. And you do what you have to to protect your men. And not just your men — the people who will die if you let that man getaway.”