(CNN) -- Two Mexican nationals were charged Monday in the death of a U.S. Coast Guardsman, whose succumbed to a traumatic head injury after his boat was rammed off the Southern California coast.
The suspects -- Jose Meija-Leyva and Manuel Beltran-Higuera -- are charged with killing a U.S. government officer while that officer was on duty in the death of Chief Petty Officer Terrell Horne III, the U.S. attorney's office for the central district of California said in a news release.
Neither man was asked to enter a plea when they appeared Monday afternoon in federal court, where Magistrate Judge Victor Kenton ordered them held without bond, U.S. attorney's office spokesman Thom Mrozek said. A preliminary hearing is set for December 17, and their arraignment is set for December 21.
Calls placed Monday evening to the separate attorneys representing the two suspects were not immediately returned.
Early Sunday morning, the crew of a Coast Guard patrol aircraft spotted a panga boat near Santa Cruz Island, suspecting "it was engaged in illegal activity," said Capt. James Jenkins. A panga is an engine-powered work boat often used off the coast of Mexico or Central America and is typically 25 feet to 45 feet long, Jenkins said.
The aircraft's crew alerted the captain of the Cutter Halibut, an 87-foot patrol boat, which headed to the scene and noticed the panga "operating with no lights." A small boat was dispatched from the Halibut, and it headed closer to the suspect vessel.
Then, the panga accelerated and slammed into the small boat, forcing Horne and another Coast Guard member overboard. Two Coast Guard colleagues on the same small boat recovered their shipmates, and all four boarded the Halibut as it headed to the nearest port.
Having suffered a traumatic head injury, Horne was pronounced dead by emergency medical personnel upon his arrival on shore at Port Hueneme. The other Coast Guardsman tossed overboard was treated at a hospital for "relatively minor injuries" and released later Sunday morning, Jenkins said.
The panga boat fled.
Around 5 a.m. Sunday, about four hours after the initial crash, the panga was located about 20 miles north of the U.S.-Mexico border, according to the criminal complaint.
Coast Guard officers pulled up and ordered the boat's occupants, at gunpoint, to exit the boat. They refused to comply, and the panga raced away. It then stalled, refused further orders, and sped away again, the complaint said.
In the third try, a Coast Guard officer pepper-sprayed both men on the panga. That boat's driver was detained after a struggle with Coast Guard officers, while his passenger was "detained without incident," the criminal complaint said.
The suspects had entered the United States "illegally from Mexico," according to the document.
Meija-Leyva told investigators "he was taking gasoline to some lost friends north of Los Angeles," and Beltran-Higuera said he'd been offered $3,000 to transport gas to a waiting panga boat off the U.S. coast. As for what happened early Sunday, Beltran-Higuera said he heard people yelling "Stop! Put your hands up!" then "a series of gunshots before the Coast Guard vessel collided with the panga," the criminal complaint stated.
The same day the two suspects were in court, colleagues of Horne remembered him as a devoted Coast Guardsman and beloved friend. The Redondo Beach, California, resident, 34, was second-in-command on the Cutter Halibut.
"Words cannot express (the) admiration that I have for him," said the ship's commander Lt. Stewart Siebert, as he fought back tears. "He was my friend, he was my confidant, he was the glue that held my crew together."
CNN's Greg Botelho contributed to this report.