SUSPECT EXTRADITED AND CHARGED IN 2018 SLAYING

Martinez accused of fleeing to Mexico after shooting in San Diego

SAN DIEGO

A man accused of fatally shooting another man two years ago outside a gym near the Midway District and then fleeing to Mexico has been extradited to San Diego where he pleaded not guilty Wednesday to murder and other charges, according to authorities.

Ernesto Castellanos Martinez, 44, is accused of killing 27-year-old Alexander Mazin on Feb. 25, 2018, outside the 24 Hour Fitness on Midway Drive and Kemper Street. He also faces special-circumstance allegations that he used a gun and had been lying in wait for the victim.

In addition, Castellanos — whose name appears in court documents as Ernesto Martinez — is charged with felony stalking of his ex-girlfriend throughout 2017 and into early 2018, as well as a misdemeanor charge of battery against her two weeks before the killing of Mazin, whom she had been seeing.

Castellanos was ordered held in county jail without bail. Normally, a charge of murder with special-circumstance allegations would allow prosecutors to seek the death penalty, but U.S. extradition agreements with Mexico prohibit that.

If convicted, Castellanos faces a sentence of life in prison without parole.

An off-duty sheriff ’s deputy reportedly witnessed the Sunday-morning slaying. The deputy, Jerome Agnew, told Onscenetv he heard two gunshots that sounded like firecrackers and went to his patio. From there, he saw a gunman chasing two men across a nearby parking lot.

Mazin died at the scene, according to police.

Later that same day, San Diego SWAT officers surrounded a building in North Park where the alleged gunman was believed to be holed up. But when the tactical team obtained a warrant and entered an apartment in the building hours later, the suspect was not inside. According to the San Diego County District Attorney’s Office, Martinez fled to Mexico and remained on the run for a little more than two years, until his capture and extradition in March. He’s expected to be arraigned Wednesday via video because the courts are closed due to the coronavirus pandemic.

Jail records showed Castellanos was booked March 14 into San Diego Central Jail on suspicion of murder and felony stalking.

A spokeswoman said the defendant’s arraignment was delayed more than seven weeks due to the coronavirus-related court closures.

San Diego County Crime Stoppers had offered $1,000 for information leading to Castellanos’ arrest, and Mazin’s friends and family put up an additional $8,000 reward.

Castellanos was reportedly a mixed martial arts and boxing coach. A photo of him released by Crime Stoppers showed him posing shirtless and in a fighting stance at a Midway District mixed martial arts gym.

The District Attorney’s Office offered no details about where or how the defendant was found, saying only that the office’s extradition unit brought him back from Mexico “with the help of law enforcement partners in Mexico, the U.S. Marshals Service and the San Diego Police Department.”

Staff writer Teri Figueroa contributed to this report.

alex.riggins@sduniontribune.com