LOS ANGELES (AP) — A report filed with federal regulators reveals the offshore pipeline that spilled tens of thousands of gallons of crude oil off the Southern California coast in October did not have a fully functioning leak detection system.

The report was filed by pipeline operator, Beta Offshore, a subsidiary of Houston-based Amplify Energy. It reveals Amplify is investigating whether personnel or control room issues contributed to the accident. It gives no new clues about a suspected anchor strike from a drifting cargo ship that is believed to have damaged the pipe perhaps months before the roughly 25,000-gallon spill.

The report, filed last week, was obtained by The Associated Press through a public records request.