Several agencies have ruled out a missile launch as the cause of a vapor cloud off the Southland coast captured by a television station's helicopter, a Pentagon official told a radio station on Wednesday.

“We have confirmed through the different parts of the Department of Defense that are involved in missile and rocket activity that there was no military launch, either a scheduled or an inadvertent one,'' Col. Dave Lapan told KNX radio. ``We have confirmed through Northern Command that they have no indications of a foreign military launch in that area.”

Possible causes of the vapor trail still under investigation include weather phenomena, amateur rockets and jet planes, Lapan told the radio station.

A Pentagon official told ABC News “We are going down the rabbit hole to look at every possibility.”

A CBS2 news helicopter crew captured footage late Monday of what appeared to be a missile in the sky northwest of Catalina Island. The video shows a point of light moving through the sky, followed by a contrail, similar to a missile being launched.

“We're looking into it,” said Ian Gregor of the Federal Aviation Administration. “We did not approve of any commercial launches in that area Monday.”

The North American Aerospace Defense Command and the United States Northern Command issued a statement saying federal authorities were aware of the “unexplained contrail.”

“At this time, we are unable to provide specific details, but we are working to determine the exact nature of this event,” according to the statement. “We can confirm that there is no threat to our nation and from all indications this was not a launch by a foreign military. We will provide more information as it becomes available.”

Officials at Vandenberg Air Force Base and Naval Air Station Point Mugu told the Los Angeles Times they were not responsible for the launch.