A mystery vapor trail that was filmed off the coast of southern California and looked like a missile launch was likely caused by a plane, the Pentagon said on Wednesday, closing its case on the incident.
"With all the information that we have gathered over the last day and a half about this condensation trail ... we have no evidence to suggest that this was anything other than a contrail caused by an aircraft," said Colonel David Lapan, a Pentagon spokesman.
The image was caught on tape by a KCBS news helicopter on Monday evening at rush hour. Video showed a billowing contrail apparently rising from the water about 50 km west of Los Angeles and north of Catalina Island.
Contrails are created by streaks of condensation from the exhaust of jet aircraft flying at high altitudes.
Initial reports that the condensation trail appeared to be that of a missile prompted Defense Department officials to begin looking into the issue.
Col. Lapan said the Pentagon had tried to determine "whether our activities - missile, rocket, etc. - were the source of this."
It took 36 hours to investigate because officials had to talk to the different agencies and services that might have been involved - the Navy, Air Force, the Missile Defense Agency, U.S. Northern Command and the North American Aerospace Defense Command as well as other U.S. agencies like the Federal Aviation Administration.
"It's a matter of ... running down all of those different leads," Col. Lapan said. "I mean, going out and having everybody scrutinize everything that they had in terms of information to be able to piece together."
"Without getting into specifics, we have looked at lots of data sources," he said.
The ultimate conclusion?
"The Department of Defense ... is satisfied that the contrail was likely caused by an aircraft," Col. Lapan said.