An unleashed dog is the probable cause of death of an endangered Hawaiian monk seal found with puncture wounds to her head and flippers last month on Oahu, federal authorities announced Thursday.

The carcass of the 4-month-old female pup RS48, also known as Ho‘omau Lehua, was recovered by federal authorities June 12 on the North Shore, according to the National Oceanic and Atmospheric Administration.

The seal pup was last seen swimming June 6 in the same general area where a necropsy conducted by NOAA suggests she died two days later.

Ho‘omau Lehua is the second young seal that appears to have been killed in a dog attack, federal officials said in a press release.

In 2014, NOAA volunteers found a 2-week-old seal pup dead on a Kauai beach. Federal regulators later determined that the seal pup had been mauled by a dog. Four other seals suffered punctures and scratches in the dog attack but survived their injuries.

One of the seals that survived the deadly 2014 dog attack was found bludgeoned to death on a beach in Anahola less than six months later.

Even when a dog attack is not immediately fatal, the resulting injuries can develop life-threatening infections. Dogs can also transmit diseases to monk seals.