Agent Anthony Fazio testified as a preliminary hearing got underway for Carlo Gallopa Mercado, who is charged with murder in the deaths of Ilona Flint, Salvadore Belvedere and his older brother, Gianni.
Salvadore Belvedere and Flint, both 22, were found mortally wounded at the Westfield Mission Valley Mall early last Dec. 24. The body of 24-year-old Gianni Belvedere was found in the trunk of his missing car in Riverside on Jan. 17. He was engaged to Flint.
Fazio testified that Mercado, 29, was stopped about 4:45 a.m. on Jan. 18 at the San Clemente checkpoint when an agent noticed a weapons case in the back seat of his Ford Explorer.
Fazio said Mercado admitted having an assault rifle in the car, but didn't mention two loaded handguns -- a .22-caliber and a .45-caliber -- magazines and boxes of ammunition found in a backpack on the front seat.
A homemade silencer was also found in the vehicle, Fazio testified.
A police firearms expert who also testified Tuesday said the bullets that killed all three victims were fired from the same .22-caliber handgun. The witness was not asked whether the slugs matched the gun found in Mercado's car.
James Yates of the Department of Homeland Security testified that Mercado was "drained of emotion'' and couldn't explain where he was going when agents at the checkpoint interviewed him.
Yates said he and another agent contacted Mercado's family to make sure they were safe and to find out about the defendant's "odd'' behavior.
The weapons were seized, Mercado was released, and the case was referred to the state Department of Justice.
Mercado was arrested for the shootings of Flint and the Belvedere brothers in late June. He was awaiting sentencing after pleading guilty to possession of a silencer.
Judge Eugenia Eyherabide will decide at the end of the preliminary hearing, which resumes tomorrow, whether the evidence is sufficient to hold Mercado for trial.