AUSTIN -- In November of 2011, Cypress Bend in Southeast Austin became the scene of what police describe as a unusual case that's been very difficult to crack.
"We don't have a lot of incidents of 13-year-olds being stabbed in Austin," said Sgt. Bryan Miller with the Austin Police Department.
But it happened to Luis Lopez Flores in the street when his attacker left him to die. Police say he had an argument with then 17-year-old Roman Arroyo, and when Flores walked away, Arroyo followed him and killed him.
Police still don't know why or if they even knew each other.
APD's homicide division received several tips in the last few weeks, after no leads for months following the crime.
"They think he might have fled to Mexico at that point. That's some of the information we've got and some of the information were getting is that he could be back in Austin now," said Sgt. Miller.
It's encouraging information for Maria Flores, who lost her oldest son. She calls him her "little angel."
Through an interpreter, Flores told KVUE, "This pain, I don't wish it on anyone, especially a mom."
Flores is pleading for help, hopeful that someone will see the photo again, know where to find Arroyo, and call police.
"If anyone knows or has heard rumors or has heard comments about him or any kind of information, I ask for your help, please. Please call the police so that we have new steps to follow...to ask for justice for my son, so that he can have peace," Flores said.
Sgt. Miller did not work the original crime scene, but wants to find closure for Flores before her son's death becomes another cold case.
"This one was especially tough on the family," he added. "So what we're looking for is to help bring closure to the family as well as bring justice to the victim.
Arroyo's arrest warrant states he is wanted for murder, and his bond has been set at $600,000.
If you have any information on his whereabouts, you are asked to call police at (512) 477-3588 or Crime Stoppers at (512) 472-TIPS.
A reward of $1,000 is available to anyone who provides information leading to an arrest.