Two Somali men were sentenced to life in prison for their roles in a pirate attack on a cruising boat that left four Americans dead, including a Marina del Rey couple, U.S. attorneys said.

U.S. District Judge Mark S. Davis sentenced Muhidin Salad Omar, 30, and Mahdi Jama Mohamed, believed to be 23 or 24 years old, both of Somalia, Oct. 3 in the deaths of Jean and Scott Adam, of Marina del Rey, and Phyllis Macay and Bob Riggle of Seattle, according to the U.S. Attorney’s Office Eastern District of Virginia. The four Americans were murdered by a group of Somali pirates Feb. 22 while making a passage towards Oman in the Arabian Sea on the Adams’ 52-foot S/V Quest.

Omar previously pled guilty on May 25 and Mohamed pled guilty on May 26 to piracy under the law of nations, a U.S. attorney spokesperson said.

The sentencing comes more than a month after two other Somali men, Ali Abdi Mohamed, 30, and Burhan Abdirahman Yusuf, 31, were sentenced to life in prison in the killings of the four Americans.

“Somali piracy is a scourge on the world stage, and it continues to grow more widespread and more violent,” said Neil MacBride, U.S. attorney for the Eastern District of Virginia.

“Armed attacks on the high seas carry a very real threat of death to those taken hostage, a threat that was tragically made evident in this case. That threat remains for hundreds of hostages held hostage in Somalia, and a life sentence sends a strong message to anyone who chooses to engage in piracy against U.S. interests that they will face severe consequences.”

The investigation of the case is being conducted by the FBI and the Naval Criminal Investigative Service.