SAN ANTONIO -- Bexar County cold case investigators are closing in on the unsolved murder of a 20-year-old San Antonio man, but they said they need the public's help to track down a person of interest to crack the case.

"I went crazy. I knew instantly he was dead," said Juanita Rodriguez, the victim's mother.

Rodriguez last saw her son, Anthony, on Jan. 11. He was gunned down in a drive-by shooting at a party held outside a private business in southwest Bexar County.

"He wanted to be a math teacher," said Rodriguez. "He was fun, loveable and he had a lot of friends."

One person has been arrested in connection with the slaying, but investigators believe two others were involved in the killing.

Investigators have named Juan Garces, 18, as a person of interest. He has been known to frequent the Somerset area.

"We need somebody to pinpoint who was in the vehicle and who exactly was shooting at this party," said Adrian Ramirez, a cold case investigator with the Bexar County Sheriff's Office.

Rodriguez said she hopes all those connected with her son's death will be found.

"I think they should arrest all three of them," she said. "One of them shot him. They should take them all in."

Rodriguez said she believes those responsible for her son's death will strike again if they aren't taken off the streets.

"A killer will always be a killer," Rodriguez said. "I'm begging for them to come forward, say something, call the detective."

Anyone with information on Garces' whereabouts or any other information that could help detectives is asked to call Crime Stoppers at 210-335-6041.