Coast Guard investigates vessel owner, operator following California oil spill

The owner and operator of a ship will be questioned as part of another marine casualty investigation after a pipeline leaked thousands of gallons of crude oil into the Pacific Ocean, according to the U.S. Coast Guard.

The agency has designated the MSC Mediterranean Shipping Company, the owner of the MSC DANIT, and the Dordellas Finance Corporation, the operator of the vessel, as parties of interest into the investigation into a Jan. 25 incident in which an anchor was dragged during a heavy weather event that impacted the Ports of Los Angeles and Long Beach.

The incident occurred in "close proximity" to the underwater pipeline known as Elly, which was the source of the leak that spilled up to 144,000 gallons of oil into the Pacific Ocean, according to the Coast Guard.

Investigators from the Coast Guard boarded the container ship at the Port of Long Beach on Saturday as part of the probe, authorities said. The "party in interest" designations provide the owner and operator of the MSC DANIT the opportunity to be represented by counsel, to examine and cross-examine witnesses, and to call witnesses who are relevant to the investigation, according to the Coast Guard.

The investigation into the oil spill is ongoing.

The pipeline was split open after a section measuring about 1 mile long was pulled along the ocean floor after it was hit by a shipping container, to examine and cross-examine witnesses, and to call witnesses who are relevant to the investigation, the Associated Press reported.

Cleanup crews are continuing to remove crude oil from California's southern coast after thousands of gallons were leaked from a broken pipe earlier this month.

The U.S. Coast Guard has removed about 1,281 gallons of an "oily water mixture" from the Pacific Ocean since the pipeline operated by Amplify Energy about 4.5 miles off the coast of Huntington Beach since the leak was reported on Oct. 2.

Thousands of gallons of oily water mixture have been recovered from the water and beaches by the Coast Guard and other response teams. Dozens of oiled wildlife have also been treated by veterinarians.

ABC News' Will Gretsky contributed to this report.