On December 18, 2014, at 1723 central standard time, a Cessna 310J airplane, N700MA, experienced a left main landing gear collapse after landing at the San Antonio International Airport (KSAT), San Antonio, Texas. The pilot and two passengers were not injured and the airplane sustained substantial damage. The airplane was registered to Laguna Verde Leasing Inc., Wilmington, Delaware, and operated by a private individual under the provisions of 14 Code of Federal Regulations Part 91 as a personal flight. The flight departed from the Castroville Municipal Airport (KCVB), Castroville, Texas. The pilot reported that after departure he noticed the landing gear did not retract as usual. He began to troubleshoot the problem and actuated the gear down lever. The landing gear did not extend and the green landing gear light in the cockpit did not illuminate. The gear was recycled and the gear again did not extend. The pilot continued to the destination airport and had air traffic controller observe the position of the landing gear. The tower controller reported that the landing gear appeared to be down and cleared the pilot to land. During the end of the landing roll when the airplane was slow, the left landing gear retracted. The airplane sustained substantial damage to the left wing spar. The responding Federal Aviation Administration (FAA) airworthiness inspector examined the airplane and reported that the landing gear compartment was dirty and covered in oil and debris. The examination did not reveal the reason for the landing gear retraction. The airplane was not able to be examined a mechanic.